The present invention relates to adapters for rerouting electrical wires or cables. In particular, the present invention relates to terminal reversing blocks for changing the direction of electrical cables extending out of an electrical disconnect device. As used herein the term “cable” will be used to describe electrical conductors including wires, cables, busbars or other conductors.
High current electrical disconnect devices, such as pull-out switches or circuit breakers for example, are typically connected to thick, heavy electrical cables. The cable connectors of such disconnect devices are commonly referred to as terminal collars. The terminal collars conventionally are located on opposite sides of the housing of the disconnect device. This arrangement arises from the fact that the disconnect device internally has a selectably bridgeable gap in its conductors so there are two naturally-defined, physically separate “sides” of the conductive path through the disconnect. Thus, it is most convenient to physically locate the cable connectors that terminate the two sides of the electrical path on separate sides of the disconnect device. This choice is reinforced by the space requirements of the large cables. It is convenient to route the incoming and outgoing cables on opposite sides of the disconnect device to keep them out of each other's way.
The electrical disconnect device is typically mounted inside an enclosure, such as a junction box or a cabinet. Heavy electrical input cables bring power into the electrical disconnect device and similarly large electrical output cables carry power out of the electrical disconnect device. The diameter of the electrical input and output cables is such that the cables do not bend easily. Consequently, if a linear, single-direction arrangement of the cables is unworkable in a particular situation large spaces are required to bend an electrical input or output cable around to effect a variation in a cable's direction.
As mentioned above, high current electrical disconnect devices have cable retaining structures such as terminal collars which include lugs with clamping screws. For example, the disconnect device can be a pullout fusible switch that is configured to have electrical input cables enter into the bottom of the switch and electrical output cables exit out of the top of the switch, as seen in U.S. Pat. No. 4,536,046 to Erickson, the disclosure of which is incorporated herein by reference. Another example of an electrical disconnect device is a load switch or circuit breaker, as seen in U.S. Pat. No. 4,363,063 to Erickson, the disclosure of which is incorporated herein by reference.
It is often desired to have the electrical input and output cables routed in directions other than the conventional opposite directions. For example, it is sometimes advantageous to have the output cables routed in the same direction as the input cables. That is, the input and output cables are essentially right next to each other. This may be due to limitations on space in the enclosure that contains the electrical disconnect device. The current method to accomplish this is to bend the electrical output cables around in an arc to route the output cables in the same direction as the input cables. Due to the large diameter of high power cables, the radius about which they will bend is large. This means the space required to bend the cables in a reversing arc may be larger than is available. In addition, the extra lengths of cables or cables required to make such an arc increases the cost.
This problem is illustrated in
Thus, there remains a need for a way to reroute electrical output cables from an electrical disconnect device in a minimum of space. There also remains a need for a way to adapt such electrical cable routing to industry standard electrical disconnect devices, such as pull out switches or circuit breakers for example.
The present invention provides a terminal reversing block that connects to a standard electrical disconnect device. The terminal reversing block has a dielectric housing that mounts therein one or more conductive terminals. Each terminal has a mating portion, a body portion, and a connecting portion. The mating portion is engageable with a conductor of the electrical disconnect device. The connecting portion is engageable with an output cable by means of a terminal collar. The body portion joins the mating and connecting portions. The connecting portion of the terminal is located remotely from the mating portion.
The terminal reversing block's housing can be sized and shaped to fit above or below the electrical disconnect device. The terminal reversing block is preferably sized and shaped to have the same or roughly the same length and width as the electrical disconnect device, thereby minimizing the length and width required for the completed assembly of the terminal reversing block and electrical disconnect device. The body portion of the terminal may include an offset section that separates the longitudinal axes of the mating portion and connecting portions thereby providing easy access to the terminal collars on the electrical disconnect device and the terminal reversing block. Alternatively, the terminal reversing block can be sized and shaped to extend out from at least one side of the electrical disconnect device so as not to increase the height of the electrical disconnect device, thereby minimizing the height required for the enclosure of the terminal reversing block and electrical disconnect device.
These and other desired benefits of the invention, including combinations of features thereof, will become apparent from the following description. It will be understood, however, that a device could still appropriate the claimed invention without accomplishing each and every one of these desired benefits, including those gleaned from the following description. The appended claims, not these desired benefits, define the subject matter of the invention.
A terminal reversing block 10 in accordance with the present invention is shown in
In this embodiment the terminal reversing block is a three-pole device. Accordingly, it has three terminals 14. It will be understood that different numbers of poles and terminals therefor could be provided depending on the needs of a particular application. Housing 12 and terminal 14 can be made from any industry standard dielectric and conductive materials, respectively. By way of example only, housing 12 may be molded of an insulator resin, usually a phenolic resin, and the terminals 14 are made of copper with a finish of silver plate and protective dip.
Details of the housing's construction are illustrated in
The housing's shell section further includes a bed or floor 22 which extends between the side walls 16, 18 and end wall 20. To accommodate the angled portions 16A, 18A of the side walls the floor 22 has an angled front portion 22A. The floor is located somewhat above the bottom edges of the side and end walls, as seen in
In this three-pole embodiment the shell is subdivided into three terminal-receiving chambers 34A, 34B, 34C by two partitions 36, 38. The partitions extend generally parallel to the side walls 16, 18. Thus, the partitions also include angled portions 36A, 38A. Each partition 36, 38 also has a pair of enlarged or thickened portions 36B, 38B, respectively. The enlarged portions each accommodate a threaded bore 40 therein. The threaded bores receive mounting screws (not shown) which extend through an electrical disconnect device to retain the device on the shell. Cylindrical protrusions 42 surround the bores 40 and extend a short distance above the top land of the partitions 36, 38. These protrusions fit into small depressions (not shown) in the underside of an electrical disconnect device mounted on the shell to serve as locators for the disconnect device.
The shell portion of the housing 12 has a series of ribs 44 on the underside of the floor 22, some of which are seen in FIGS. 2 and 5-7. Some of the ribs carry small feet 46, which lift most of the housing off a surface to which it is mounted to facilitate air flow around the underside of the housing. The shell is completed by four mounting tabs 47 which extend from the bottom edges of the side walls 16, 18. The tabs have holes therein for receiving a mounting screw (not shown). It will be noted that the bottom surfaces of the mounting tabs are coplanar with the bottom edges of the feet 46.
Attention is now directed to the case section of the housing. The case section is a box-like portion attached to the front of the shell section. In fact, the extensions 16B, 18B of the side walls define the sides of the case. The case further includes a transverse rear wall 48 and a top wall 50. Depending from the top wall 50 and attached at the rear wall 48 are four vertical interior walls 52A, 52B, 52C and 52D. At the front edge of the interior walls and adjoining the underside of the top walls is a retention ledge 53 (
Assembly of the terminal reversing block is as follows. First, a terminal 14 is placed in each of the housing's terminal-receiving chambers 34A-C with the terminal's mounting apertures 69 aligned with the bores 24A, 24B in the housing floor 22. Then the terminal mounting bolts 26A, 26B are installed to fix the terminal in place. It will be evident that the terminal's offset portion 68 lies above the angled portion 22A of the floor and the terminal's connecting portion 60 extends into the one of the collar-receiving pockets MA-C. Next the terminal collars 72 are placed in the pockets MA-C. With the C-shaped clip removed, the lug 74 is inserted into the pocket from the front but with the roof 78 lower than its ultimate position so the roof will clear the lower edges of the retention ledges 53. At this point the connecting portion 60 of the terminal will extend into the central passage 76 of the lug but somewhat above the floor 80. Once the lug is far enough into the pocket to clear the retention ledges 53, the lug is pushed upwardly so it fits in behind the retention ledges. This upward movement of the lug carries the foot's protrusion 82 into engagement with the bore 70 in the terminal's connecting portion 60 and places the connecting portion in engagement with the top surface of the floor 80. Then the C-shaped clip 84 is placed over the connecting portion 60 and bottom of the floor 80. The C-shaped clip has sufficient spring force to retain it in place on the lug's floor. The clip 84 holds the terminal collar 72 on the terminal's connecting portion 60 and prevents the terminal collar 72 from falling out the bottom of the pocket 54. It can be seen that once a cable is placed in the central passage, a driver tool, e.g., a hex driver, can be placed through one of top wall openings 56 to engage the clamping screw 86 and advance it into the central passage, thereby clamping the cable between the screw and the top surface of the C-shaped clip 84.
Having described the terminal reversing block 10, we can now turn to the electrical disconnect device. One embodiment of an electrical disconnect device 88 is shown installed on a terminal reversing block 10 in
The pullout switch 88 has a housing 90 that has front and rear case sections similar to that of the terminal reversing block. The front case section has three cavities 91 which are generally similar to the pockets 54 in the terminal reversing block. Terminal collars 92 similar to collars 72 are disposed in the cavities 91 (the rear case section is shown with its collars removed). C-shaped clips 93 (
As seen in
It is pointed out that the offset portion 68 of the terminal 14 results in the centerline of the terminal collars in the reversing block being laterally spaced from the centerline of the terminal collars in the disconnect device 88. This is best seen in
It will be understood that there are numerous modifications of the illustrated embodiments described above which will be readily apparent to one skilled in the art, such as many variations and modifications of the terminal reversing block and/or its components, including combinations of features disclosed herein that are individually disclosed or claimed herein, explicitly including additional combinations of such features. Also, there are many possible variations in the materials and configurations. These modifications and/or combinations fall within the art to which this invention relates and are intended to be within the scope of the claims, which follow. For example, instead of routing the output cables in the same direction as the input cables, in some instances it may be desirable to route the output cables perpendicular to the input cables. In this case the terminal reversing block would be configured to have its output terminal collars facing to one side of the housing. Also, while the terminal collar is a preferred device for maintaining a cable in contact with the connecting portion of the terminal, other arrangements could be used to hold the cable against the terminal. For example, an internally-threaded sleeve for receiving the clamping screw 86 could be mounted in the case portion of the housing and aligned with the collar-receiving pocket such that the clamping screw is engageable with a cable lying above the terminal's connecting portion 60. Finally, it will be understood that references to input and output cables are for purposes of distinguishing between two sets of cables and not for implying what the cables are connected to in the rest of the circuit. Thus, depending on the needs of a particular circuit, either an input or output cable could be connected to the line side of the circuit and either an input or output cable could be connected to the load side of the circuit.
This application claims the benefit of U.S. Provisional Application Ser. No. 61/288,805, filed Dec. 21, 2009, the disclosure of which is incorporated by reference herein.
Number | Date | Country | |
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61288805 | Dec 2009 | US |