The present invention relates generally to barriers to pedestrians or vehicles, and more particularly to fences and fence components assembled by a resistance projection welding process.
The present invention comprises a barrier formed from at least one elongate rail and at least one vertical upright member. The rail is characterized by a flat web and a pair of opposed side walls which extend from the web to define a rail channel. A weld-forming region which projects within the rail channel is formed in at least one of the side walls. The upright member is partially situated within the rail channel and is secured to the rail by a weld. The weld is formed within the rail channel at the weld-forming region, between the side-wall and the upright member.
The invention further comprises a method of assembling a barrier from at least one conductive upright member and at least one elongate conductive rail. The rail is characterized by a flat web and a pair of opposed side walls which extend from the web to define a rail channel. A weld-forming region which projects within the rail channel is formed in at least one of the side walls. The upright member is transversely positioned within the rail channel such that it contacts the weld-forming region. The upright member is contacted with an electrode having a first polarity, while the rail is contacted with an electrode having a second polarity opposed to the first polarity. A welding current is transmitted between the rail-contacting electrode and the upright member-contacting electrode to cause the weld-forming region to form a weld within the rail channel. This weld joins the upright member to the rail.
The present invention comprises a barrier, such as a fence, balustrade, or gate, formed from at least one, and preferably a plurality of, elongate rails, and at least one, and preferably a plurality, of upright members.
The fence 10 preferably comprises a plurality of spaced vertical posts 12, preferably identical in construction, each of which is securely anchored at its base into a substrate 14, such as the ground, or an underground mass of concrete. The posts 12 are situated along the boundary of the area to be enclosed by the fence 10, with a post spacing which is adequate to impart strength to the fence 10 and to securely anchor other fence components. In the
Each post 12 is preferably formed from a strong and durable material, such as sheet steel or aluminum. In a preferred embodiment of the present invention, the sheet used to form the post 12 is characterized by a thickness of 0.059 inches. In order to enhance its resistance to corrosion, the sheet is preferably subjected to a pre-galvanizing treatment. The pre-galvanized sheet is then subjected to a cold rolling process to form the rail into a tubular configuration, preferably having a rectangular cross-section. Alternately, the post may be formed with a circular cross-section. After cold rolling is complete, a polyester powder coating is preferably provided in order to further enhance corrosion resistance of the post 12.
With continued reference to
While any number of rails may be provided for each panel 16, either two rails, as shown in
As best shown in
Each rail 18 is preferably formed from a strong, durable and conductive material, such as a sheet steel or aluminum. In a preferred embodiment of the present invention, the sheet is characterized by a thickness of 0.075 inches. In order to enhance its resistance to corrosion, the sheet is preferably subjected to a pre-galvanizing treatment. The pre-galvanized sheet is then subjected to a cold rolling process to produce the cross-sectional shape shown in
At least one, and preferably both, of the side walls 24 and 26 include a weld-forming region 30 which projects within the rail channel 28. In the embodiment of the rail 18 shown in
When the weld-forming regions comprise ridges, they are preferably formed during the cold rolling process. One or more continuous longitudinal scores 32 are preferably formed in the surface of the sheet which will not define the rail channel 28. These scores 32 cause ridges to protrude from the opposite surface of the sheet. When that surface is formed into the rail channel 28 by the cold rolling process, each of the protrusions will define an elongate ridge which projects within the rail channel 28 and comprises a weld-forming region 30, as shown in
The dimensions of each weld-forming region 30 should be selected so that the region can effectively concentrate a welding current flow. When the rail 18 is formed from a sheet having a thickness of 0.075 inches, a preferred height for the weld-forming region 30, with respect to its associated side wall, is 0.035 inches. A preferred width for the weld-forming region 30 is 0.143 inches. A pointed and or angular profile for the weld-forming region 30 is preferred.
Opposed and aligned fastener openings 34 are formed at each of the side walls 24 and 26, preferably at each of the opposite ends of the rail 18. A plurality of longitudinally spaced top openings 36 are preferably also formed in the web 22 of at least one of the rails 18, more preferably in all of the rails 18, with the possible exception of the uppermost rail 18. In the embodiment shown in
Each upright member 20 is preferably formed from a strong, durable and conductive material, such as sheet steel or aluminum. In a preferred embodiment of the present invention, the sheet used to form the upright member 20 is characterized by a thickness of 0.040 inches. In order to enhance its resistance to corrosion, this sheet is preferably subjected to a pre-galvanizing treatment. The pre-galvanized sheet is then subjected to a cold rolling process to form the upright member into a tubular configuration, preferably having a rectangular cross-section.
Each of the upright members 20 is preferably sized to be closely but clearingly received within the rail channel 28 of each rail 18, and to be closely but clearingly received through any top openings 36 formed in any of the rails 18 to which it will be attached. As shown in
As shown in
While positioned within the rail channel 28 as described above, the upright member 20 should contact at least one, and preferably an opposed pair, of the weld-forming regions 30 formed in the rail 18. When the rail 18 to which upright member 20 is to be secured includes top openings 36, as in
In the next stage of assembly, the upright member 20 is contacted with a first electrode (not shown) having a first polarity, and the rail 18 is contacted with a second electrode (not shown) having a second polarity opposed to the first polarity. Preferably, the point of contact for each electrode is near the weld-forming regions 30. A welding current is then transmitted between the rail-contacting electrode and the upright member-contacting electrode.
The welding current is of sufficient of magnitude, and applied for sufficient time, so that the electrical resistance of the rail 18 causes each of the weld-forming regions 30 contacting the upright member 20 to heat up and at least partially melt. Current flow is then terminated, and the melted portions of the weld-forming regions cool to form welds 38, as shown in
Each of the resulting welds 38 is situated within the rail channel 28 and joins the upright member 20 to the rail 18, resulting in a upright member-rail assembly. When the upright member 20 contacts an opposed pair of weld-forming regions 30, as shown in
The source of the welding current is preferably a direct current inverter power supply, such as the model IS-471B, manufactured by Unitek Myachi Corporation of Monrovia, Calif. Such a power supply converts commercial alternating current into a high frequency direct current which is fed via a transformer to electrodes in a welding head. In one preferred embodiment, a weld current of 22,000 amperes and a frequency of 1000 Hertz is used to form the welds. Preferably 2 cycles of such a current is used to form each weld.
Additional rails 18 and upright members 20 may be attached to the welded upright member-rail assembly by repeating the steps described above, until a fence panel 16 has been formed. In each such instance, an upright member 20 will be transversely positioned within the rail channel 28 of the rail 18 to which it is to be secured, so that it contacts at least one, and preferably both, of the weld-forming regions 30. The upright member 20 is contacted with an electrode having a first polarity, and the rail 18 is contacted with an electrode having a second polarity opposed to the first polarity. While the rail 18 is undergoing compression as described above, a welding current is transmitted between the two electrodes to cause the weld-forming region to form a weld 38 within the rail channel 28 which joins the upright member 20 to the rail 18. After each panel 16 is assembled as described, it is preferably provided with a polyester powder coating in order to enhance its resistance to corrosion.
The welding steps required to assembled a panel 16 from rails 18 and upright members 20 may be performed in succession, or some or all of these steps may be performed simultaneously, preferably using a separate pair of electrodes to form each weld. For example, with the panel 16 shown in
The welding steps required to form a panel 16 may advantageously be performed with automated equipment, such as a press-type welding machine. Such a welding machine may comprise one or more welding heads, each of which contains first and second electrodes which can respectively contact an upright member 20 and an associated rail 18. While current flows between the first and second electrodes, the welding machine simultaneously pressurizes the joint between the upright member 20 and rail 18. When the head is retracted, the partially assembled panel may be repositioned, so that another weld or group of welds may be formed.
With the resistance projection welding assembly method of the present invention, the welds used to assemble each panel 16 are formed internally within the rail channels 28. The exterior surfaces of the panel 16 of the present invention accordingly do not display any of the visible blemishes and marks which are characteristic of other assembly methods, such as those involving other types of welding. In addition to its role as a weld-forming region 30 within the rail channel 28, the longitudinal ridge formed in each rail 18 also enhances the strength of the rail 18.
As best shown in
When the panel 36 is installed as a fence 10, each rail 18 of the assembled fence 10 is supported at opposite ends by brackets 40 mounted on an adjacent pair of posts 12. Each rail 18 is disposed such that the channels 28 open downwardly and the side walls 24 and 26 extend substantially vertically. Within each panel 16, the incline of the rails 18 with respect to horizontal should substantially equal the incline of the terrain 44 on which pair of posts 12 supporting that panel are installed. Thus, when the fence 10 is positioned on horizontal terrain, as shown in
Because top openings 36 are formed in each of the rails 18 comprising the panel 16 in the embodiment of
With reference to
Preferably, a weld-forming region comprising a plurality of longitudinally spaced nipple-shaped projections is formed in each of the side walls 72 of the rail 70. Projections formed in the respective side walls may be arranged in direct face-to-face to opposition, or the projections may be arranged in alternation, such that a projection on one side wall is disposed opposite a gap between adjacent projections in the other side wall.
The rail 70 is preferably formed from the same materials, and by substantially the same cold rolling process as described with reference to the rail 18. The only difference in the manufacturing process for the rail 70 is that no scores are impressed on the sheet during the cold rolling process, so that no ridges are formed within the rail channel. Instead, a plurality of longitudinally spaced dimple-shaped indentations 74 are formed on the sheet used to form the rail 70, preferably before commencement of the cold rolling process. If the rail 70 includes more than one weld-forming region, then a set of longitudinally spaced indentations will be formed for each such region to be formed.
The dimple-shaped indentations should be formed in the surface of the sheet which will not define the rail channel, preferably by a press punch. These dimple-shaped indentations 74 cause nipple-shaped projection to protrude from the opposite surface of the sheet. When that surface is formed into the rail channel by the cold rolling process, each of these protrusions will define a nipple-shaped projection which projects within the rail channel and comprises a weld-forming region. The resulting rail 70 may be used, with or without top openings in the web, in any of the barriers of the present invention, such as panels 16 and 52, and fences 10 and 50.
While the present invention has been described with reference to fences, and methods for their assembly, it should be understood that the invention is equally adaptable to any barrier formed from one or more rails and one or more upright member. Other types of barriers which can be formed in accordance with the present invention include balustrades, hand rail systems, guard rail systems, and gates. When the barrier of the present incorporates a hand rail, the upper rail of the preferably includes no top openings, so that the upper rail presents a smooth and regular surface suitable for gripping by a hand.
Changes may be made in the construction, operation and arrangement of the various parts, elements, steps and procedures described herein without departing from the spirit and scope of the invention as defined in the following claims.
This application is a continuation of U.S. patent application Ser. No. 10/140,915, filed May 7, 2002, now U.S. Pat. No. 6,811,145, the disclosure of which is incorporated by reference in its entirety.
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Number | Date | Country | |
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Parent | 10140915 | May 2002 | US |
Child | 10926912 | US |