Patent Application
20120024596
The present invention is a cable clamp for securing cables and wires to an electrical enclosure. In particular, the invention relates to a flexible cable clamp that compressively engages cables and wires entering an electrical outlet box.
An electrical outlet box provides a termination point for wires carrying electrical current through buildings, houses, and other structures. Wiring entering an electrical outlet box is typically connected to an electrical device, such as a receptacle or switch, mounted within the box. The box is usually covered by a face plate having an opening that allows access to the receptacle or switch while preventing contact with the wires inside the box. Outlet boxes are often used in installations where the wires are located within a wall or ceiling. Alternatively, outlet boxes may be used in exposed-conduit wiring installations where they are mounted on the surface of a structure, such as a wall, column or ceiling.
Outlet boxes are available in a variety of configurations and sizes. The type of box selected depends on the specific requirements of the application. Outlet boxes typically include a plurality of openings which provide entry for the wires into the box. These openings are usually covered by removable portions called “knockouts,” which can be easily removed by the installer as required. With most electrical devices, the outlet box is spacious enough to accommodate a sufficient length of excess wiring so that a connected device can be removed from the outlet box and serviced without disconnecting the device from the wiring.
To install an electrical device in an outlet box, an installer pulls the end of electrical wires or cable, through a knockout opening in the box. A long enough length of wires is pulled through the knockout to allow the wires to be connected to the electrical device outside the outlet box, where the installer has more room to work. After the wires are connected to the electrical device, the device is secured in the outlet box. The outlet box is designed to have sufficient volume and depth so that the excess wires can be easily packed into the box.
In many cases, the person who runs the wires/cable into the outlet box is not the same person who installs the device. Therefore, the wires/cable may not immediately be connected to the electrical device. Even if there is no appreciable time interval in between the steps, it is easier for the installer if the wire(s)/cable is secured to the box. To facilitate the installation, a clamp is typically used to hold the wires/cable in place (i.e., in the outlet box) and thereby free the installer's hands for other tasks. The use of a clamp also allows the wires to be pulled through and held in the outlet box long before a device is connected.
Many of the prior art clamps used to retain wires/cables in steel outlet boxes require the installer to thread the wires through the clamp or require the clamp to be fastened to the box once the wires are installed. Typically, a screw is used to secure the clamp to the outlet box and, in a constricted work space, this can be cumbersome and require excessive installer dexterity. Therefore, it is desirable to provide a clamp for an electrical outlet box which can be quickly and easily removed and inserted and which allows easy installation of wires into an outlet box without the difficulties of the prior art devices.
Moreover, most steel outlet boxes that are currently available have all of the components made of steel. Wires or cables entering the box are typically clamped in place using a steel clamp and screw. Two of the objectives for the cable clamp design are low manufacturing cost and ease of use. However, in the highly competitive field of outlet box manufacture, these objectives have not been fully achieved. Moreover, the clamping systems currently used for metal electrical outlet boxes have several disadvantages. They typically require a tool to tighten the clamp against the wire or cable, which makes the installation more difficult and increases the installation time. They also use a screw to secure the clamp which increases the cost and makes the manufacture of the electrical box more complex and expensive since the box must include a threaded aperture for receiving the screw. Accordingly, there is a need for a less expensive clamp that is not made of metal and does not use a screw to attach it to the electrical box.
In accordance with the present invention, a cable clamp for securing a wire or cable in an electrical outlet box having an interior, an exterior and one or more openings therebetween is provided. The cable clamp includes a body and one or more retaining devices that define one or more apertures. The body is adapted to mount in one of the one or more openings in the electrical outlet box and each of the one or more apertures is adapted to provide a passage for a wire or cable between the interior and exterior of the electrical outlet box. The one or more retaining devices are connected to the body and each of the one or more retaining devices is adapted to secure a wire or cable in one of the one or more apertures.
In a first embodiment of the cable clamp, each of the one or more retaining devices includes a pair of pivotably movable doors. The pivotably movable doors can be attached to hinges. In addition, each of the one or more apertures can have a pair of opposing sides and the pair of pivotably movable doors can be resiliently attached to the pair of opposing sides. The pivotably movable doors pivot into the electrical outlet box when a force is applied and pivot back into the one or more apertures when the force is released.
In a second embodiment of the cable clamp, each of the one or more retaining devices includes one or more flexible arcuate members in each of the one or more apertures. Each of the flexible arcuate members is adapted to move through the aperture into the interior of the box when a force is applied from the exterior of the box. The body can also include one or more substantially rigid bases located on the second, opposing side of the aperture. A wire or cable is secured in one of the apertures between the flexible arcuate member and the substantially rigid base. The cable clamp can also include an anchoring device that is adapted to secure the body in the opening in the electrical outlet box.
In a third embodiment of the cable clamp, each of the one or more retaining devices includes two opposing flexible members. Each flexible member has a first end, a second end and a stop. Each of the one or more apertures in the body can have a pair of opposing sides and the first ends of the two opposing flexible members are attached to the pair of opposing sides. The two opposing flexible members pivot into the interior of the electrical outlet box and the stops are adapted to resiliently oppose the movement of the flexible members into the interior. The second end of each of the two opposing flexible members can have a recessed center portion that is adapted to cooperatively receive the wire or cable.
In a fourth embodiment of the cable clamp, each of the one or more apertures has a first side and a second side and each of the retaining devices includes a pivotal door. The pivotal door has an interior side and an exterior side and is attached to the first side of each of the one or more apertures. A plurality of teeth is located on the second side of each of the one or more apertures. A compressible component is attached to the interior side of the pivotal door and is adapted to oppose the movement of the pivotal door into the interior of the electrical box.
In a fifth embodiment of the cable clamp, each of the one or more apertures has a first side and a second side and each of the retaining devices includes a pivotal door. The pivotal door has an interior side and an exterior side attached to the first side of each of the one or more apertures. A plurality of teeth is located on the second side of each of the one or more apertures. The pivotal door has a substantially flat portion and a flexible member, which extends from the interior side of the pivotal door. The flexible member is adapted to oppose the movement of the pivotal door into the interior of the electrical box.
In a sixth embodiment of the cable clamp, each of the one or more apertures has a first side and a second side and each of the one or more retaining devices includes a pair of inwardly biased opposing members having a first end and a second end. The first ends of the pair of inwardly biased opposing members are attached to the first and second sides of the aperture and the second ends are adapted to cooperatively secure the wire or cable. The second ends of the pair of inwardly biased opposing members can extend into the interior of the electrical outlet box and can compressively contact each other.
In a seventh embodiment of the cable clamp, each of the one or more retaining devices includes a port having a large aperture and a small aperture. The large aperture is connected to the small aperture. The large aperture is adapted to provide a passage for a wire or a cable between the exterior and the interior of the electrical outlet box. After the wire or cable passes through the large aperture it is moved into the small aperture, which is adapted to snugly receive the wire or cable and secure it in the port.
In an eighth embodiment of the cable clamp, each of the one or more apertures has a first side and a second side and each of the one or more retaining devices includes a pair of inwardly biased opposing members having a first end and a second end. The first ends of the pair of inwardly biased opposing members are attached to the first and second sides of the aperture and the second ends are arcuately shaped and adapted to cooperatively secure the wire or cable in the aperture. The second ends of the pair of inwardly biased opposing members can extend into the interior of the electrical outlet box and can compressively contact each other.
The preferred embodiments of the clamp for an outlet box of the present invention, as well as other objects, features and advantages of this invention, will be apparent from the accompanying drawings wherein:
The present invention relates to cable clamps that fit in an opening in a steel electrical outlet box and retains wires that enter the box through the opening. The cable clamps can be made of plastic or metal or a combination of both materials. The cable clamps can have flexible or spring members that are used to secure wires or cables that enter outlet boxes through openings in one of the walls. The cable clamps fit into an opening in the outlet box and one or more flexible retaining members are attached to the sides of one or more apertures in the clamp. Wires or cables entering the outlet box are inserted through the aperture and are engaged by the flexible retaining members to secure them in place. For the present disclosure, the terms wire and cable are used interchangeably and the use of one term or the other is not intended to limit the scope of the invention in any way.
The cable clamps of the present invention can be quickly and easily attached to an opening in an electrical outlet or junction box. The clamps can be oriented as desired by the user. For example, the retaining devices can be vertically or horizontally disposed in relation to each other and the back wall of the box. In addition, the cable clamps have a low manufacturing cost and efficiently grip the wires or cables and tighten against them when a force is exerted to pull the wires or cables out of the box.
The scope of the present invention includes a variety of different embodiments of the cable clamp with different retaining devices. Preferably, each cable clamp includes two retaining devices but the invention is not limited to cable clamps having two retaining devices. The present invention is also intended to cover cable clamps having one retaining device as well as cable clamps having three or more retaining devices. Each retaining device is preferably formed by two retaining members that flexibly receive and secure a wire(s) or cable in an electrical box. In general, the common feature of the cable clamps of the present invention is that the flexible members resist removal of the wires/cable in a manner similar to a “Chinese finger grip,” i.e., the more force applied to pull the wires/cable out of the outlet box, the tighter the members grip the sides of the wires/cable.
The cable clamps include a body and one or more retaining devices attached to the sides of one or more apertures in the body. The body is adapted to mount in an opening in an electrical outlet box and the apertures are adapted to provide a passage for wires and/or cables between the interior and exterior of the electrical outlet box. The retaining devices secure the wires or cables in the apertures. The retaining devices can include a pair of pivotably movable or hinged doors, a flexible arcuate member, two opposing flexible members, a pivotal door with a compressible component and a plurality of teeth, a pivotal door with a flexible member and a plurality of teeth, a pair of inwardly biased opposing members, a port having a small aperture and a large aperture, or a pair of opposing flexible members with arcuate ends.
Referring now to the drawings,
The pivotably movable doors 116, 118 or 116′, 118′ pivot into the interior of the electrical outlet box when a force is applied from the exterior of the box and pivot back into the one or more apertures 113, 115 and 113′, 115′ when the force is released. When wires 130 enter the electrical box through either of the end walls 120, 120′, the pivotably movable doors 116, 118 or 116′, 118′ exert a compressive force against the wires 130 and secure them in place. Although
Thus, while there have been described the preferred embodiments of the present invention, those skilled in the art will realize that other embodiments can be made without departing from the spirit of the invention, and it is intended to include all such further modifications and changes as come within the true scope of the claims set forth herein.
This application is a divisional application of U.S. patent application Ser. No. 12/578,874, filed on Oct. 14, 2009, and claims priority from provisional application Ser. No. 61/196,162, filed on Oct. 15, 2008, both of which are incorporated herein in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61196162 | Oct 2008 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12578874 | Oct 2009 | US |
| Child | 13238794 | US |
