Supports – Pipe or cable – Suspended
Reexamination Certificate
2000-12-08
2003-01-21
Chan, Korie (Department: 3632)
Supports
Pipe or cable
Suspended
C248S068100
Reexamination Certificate
active
06508440
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a one-piece hanger adapted to secure conduit to channels with ledges or other similar overhead or vertical support structures. The conduit hanger can be mounted on a framing channel and is operable in various positions of holding and supporting a conduit when made secure, but it is primarily designed to suspend from or attach above an overhead channel secured by the ledges (extending lips or flanges) adjacent the open portion of the channel.
In the typical commercial building, air ducts, wiring, and other utilities are installed overhead and subsequently concealed by a suspended ceiling. It is generally known and a common practice in the construction and maintenance industries to support conduit such as gas, water, steam and/or compressed air carrying pipes, electrical cable conduit, and other associated plumbing and/or utility carrying conduits from a ceiling or other support structures. Dropped ceiling construction is heavily used in commercial and industrial buildings. Dropped ceiling construction requires reliable installation of electrical and other utility services above the ceiling. This is usually accomplished by means of suspension devices that are attachable to the support structure and adaptable for holding and supporting the conduit usually in substantially horizontal positions. Commonly, electrical and other utility conduits are strung above the dropped ceiling through supporting channels located beneath the next higher floor.
The installation of electrical wiring in building construction is subject to stringently enforced codes. Generally, wiring must be run in a protective conduit. Safety regulations require that electrical wires be strung safely and securely from each connection point to the next. Certain codes require that long runs of conduit that span an open space be supported at some interval, depending on the type of conduit. Various types of metal conduit must be supported at least every 10 feet, with certain exceptions. For non-metallic conduit, the maximum permissible number of feet between supports varies according to the diameter of the conduit. For example, conduit having a diameter in the range from a ½ inch to 1 inch must be supported at least every 3 feet, while conduit having a diameter of 6 inches need only be supported every 8 feet.
In the construction and maintenance industries, various types and sizes of pipes are used as conduits for electrical wiring, plumbing systems, and other utilities. Industrial, commercial and residential buildings normally require many different sizes and types of conduit that are hung or otherwise supported from some support structure at regular intervals along the length of travel of the conduit.
One type of conduit-holding means is referred to as a pipe strap or an outer diameter tubing pipe clamp as shown in FIG. 2 of U.S. Pat. No. 5,354,952. The prior art includes a three or four-piece hanger that has two mirror-image side members that attach with a T-shaped base into the ledges along the open portion of the channel. The four parts are the two side members, a bolt and a nut. A part of each side member is curved similarly to the conduit. The uppermost ends of the side members are flanges bent away from the curved parts to be generally parallel to each other when the pipe strap is holding a conduit in place, and the ends have a hole for a bolt to pass through. The ends are drawn together by tightening a bolt that forces the curved parts firmly against a conduit. An improvement has eliminated the nut wherein one of the side members has a threaded hole that is designed to fit around and secure the bolt. The T-shaped channel insertion portion of each side member is inserted into a channel and rotated to rest on the two ledges of the channel opening. Each side member is relatively thin so that it can be inserted parallel into the channel opening and turned so it is behind the channel ledges. The conduit is inserted between the side members and a bolt is tightened through holes in the ends.
Other prior art hangers use a framing spring nut, such as sold by Thomas & Betts, wherein a threaded insert with a spring is inserted into the channel opening. The threaded insert, after being inserted into a channel, rests on the two ledges of the channel opening. The spring resiliently engages the inner back wall of the channel opposite the channel opening to push the threaded insert into the ledges of the channel opening. The threaded insert is narrower than it is long so that the narrow side can be inserted parallel into the channel opening and turned so the longer side is behind the ledges. The insert is threaded so a bolt can be tightened through its aperture. A second part incised with advancing spiral threads that will secure the conduit can be screwed into the threaded insert. Such a second part used with a framing spring nut is a hanger shown in U.S. Pat. No. 3,310,264 that attaches to the spring nut with a bolt.
A similar conduit hanger, commonly referred to by electrical installers in the building trade as a minnie or Minerallac RTM, is shown in U.S. Pat. No. 4,479,625. A minnie is a generally U-shaped device formed of sheet metal and provided with a flat base that may contact the channel (or framing spring) and two arms that have a cylindrically rounded part shaped to fit against a conduit. The outer ends of the arms are relatively parallel to each other and have aligned holes to permit a bolt to pass therethrough. The dimensions of a minnie are such that there is space between the ends when the bolt is tightened to cause the arms to clamp the conduit tightly.
The central part of a channel often has a plurality of apertures spaced along it to allow other components to be bolted to the strut. A minnie or other hanger can be attached to the strut by a bolt that passes up through a flat base of the hanger in the central part and through the aperture and is held in place by a nut to form a complete conduit-holding device. The conduit-holding device may also include a washer on the bolt to prevent the nut from being drawn through the relatively large aperture of the channel. When a framing nut is used, it must come in different sizes to accommodate channels of different depths. The spring portion of the spring nut will be different for A and B series channels.
Another typical conduit supporting structure, commonly referred to as a trapeze because of its appearance, consists of at least two suspension members spaced apart from each other and extending downwardly from an overhead support structure with a conduit support bar attached at or near the lower ends thereof to be held in a horizontal position by the bar.
One of the problems with such trapeze structures is that the bars are cut to the desired length on the job and that the individual clamping devices that fit the bar and hold the conduits in place are selected and assembled with the bar and the conduits. This requires the electricians to spend time doing such cutting, selecting, and assembling of the components for each trapeze. Also, an electrician installing trapezes must have numerous components. This is an alternative to the present hanger, but often channels are already preexisting in commercial buildings or are installed for other purposes in addition to hanging conduit, such as holding the suspended ceiling.
Many prior art devices are complicated and cumbersome mechanisms that are inconvenient, awkward, and difficult to manufacture, handle and operate. These devices often require considerable assembly and manipulation to adequately secure the conduit in its supported position with a hanger assembly. The amount of labor required to form the parts and to assemble them into a conduit hanging system is often extensive.
Another drawback with prior art hangers is that they require assembly of more than one part during both the manufacture of the hanger and during installation of the conduit with the prior art hangers. The present hanger facilitates the rapid mounting of conduit on a channel without
Beverly Manufacturing Co.
Chan Korie
Engling Timothy J.
Lee, Mann, Smith, McWilliam Sweeney & Ohlson
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