Flip Out Fuse Assembly

The present invention relates to high voltage electrical equipment and more particularly to the confinement of replaceable components thereof such as fuses within a protective enclosure. Even more particularly the present invention relates to a mechanism for mounting fuses in an electrical system such that the circuit may be opened prior to disengaging the fuse from its contacts.

High voltage electrical equipment is inherently dangerous, thus manufacturers of such equipment take precautions in designing the equipment to reduce the hazards presented thereby. Of particular concern in the design of such equipment is the safety of personnel who are required to work on such equipment. One area which personnel must routinely encounter is the fuse mounting and enclosure area. The fuses are replaceable circuit elements which must be readily removed and replaced in the circuit, thus necessitating opening and closing the circuit in what may be an energized condition. In as much as live parts are necessarily present at or near the fuse, these elements are oftentimes enclosed within protective cabinets. In some instances these cabinets have been made from metal with non-conductive barriers interposed therewithin. The present invention and its predecessors are of a particular genre known as "dead front" switchgear. Previous designs have utilized mounting panels which have supported the fuse elements in a common enclosure with an electrical contact, with the panel pivotally mounted such that the entire panel carrying the fuse pivoted 180.degree. about a horizontal axis to position the fuse in a circuit open or circuit closed position. A complex linkage arrangement was used to actuate the mechanism, thus it was somewhat cumbersome. Further, the panel had to rotate the full 180.degree., otherwise personnel working on the switchgear would have an unreliable barrier between themselves and a live high voltage terminal.

It is the object of the present invention to provide a dead front fuse mounting which does not require complex linkages to operate and which provides a dependable means for placing a barrier between personnel and the high voltage contact.

Yet another object is to provide a dead front panel with a simple, yet efficient, interlock mechanism to prevent inadvertent panel openings.

These and other objects and advantages of my invention are accomplished by the use of a flip out mounting which trips a barrier sealing shutter whenever the fuse is moved to an open circuit position. Additionally, the fuse cannot be so moved until one side thereof has already been disconnected from the circuit.

Apparatus embodying features of my invention are depicted in the accompanying drawings which form a portion of this disclosure and wherein:

FIG. 1 is a partial perspective view of the front compartment of switchgear utilizing my apparatus;

FIG. 2 is a sectional view in side elevation showing my apparatus within a protective enclosure in the circuit closed position;

FIG. 3 is a sectional view in side elevation showing my apparatus in the circuit open position;

FIG. 4 is a sectional view taken along line 4--4 of FIG. 1;

FIG. 5 is a front elevational view of the mounting plate;

FIG. 6 is a partial sectional view taken along line 6--6 of FIG. 1.

Referring to the drawings for a better understanding of the invention, it should be noted that the present invention is an improvement over previous components used for similar purposes in high voltage electrical equipment, therefore it should be understood that the representation shown in the drawings are illustrative of the general nature of my invention and are not limited to specific associated electrical equipment. My apparatus is housed in an outer cabinet 11, partially shown in FIGS. 1-3, as is common practice in the industry. The cabinet 11 has a forward compartment 12, central compartment 13, and rear compartment 14. It should be understood that "forward" and "rear" merely serve to distinguish the outer compartments.

The forward compartment 12 encloses an elbow connector 16 for each phase of the high voltage circuit. Such elbow connectors are commonly used in the industry and will not be described in further detail, except to define a mating portion 17 and a line portion 18. The mating portion 17 includes a plug type connector which mate with a receptacle within a bushing 19, shown in FIG. 2. The mating portion has an eye 21 which may be engaged by a hot stick to disconnect it from the circuit. The bushing 19 is mounted on a plate-like member 22, having outer flanges 23 extending into compartment 12. Plate-like member 22 is hingedly mounted at 24 to a partition 25 wall separating forward compartment 12 and central compartment 13 and is dimensioned so as to fit over an opening 26 in the wall 25. As shown in FIGS. 1 and 3, the hinge-like mounting 24 permits the plate-like member 22 to pivot outwardly into compartment 12.

As may be seen in FIG. 6 mounted to the wall 25 immediately above opening 26 is a latch plate 27, which may be an angled member having one leg thereof extending normal to the plane of the wall, with a plurality of holes therein for receiving latch bars. A pair of latch bars 28 and 29 are slidably mounted to the plate-like member 22 so as to be selectively engaged within said latch plate 27 in apertures found in the flange 23. Pivotally connected to the latch bars 28 and 29 at the ends thereof distal the latch plate 27 is a generally U-shaped latch operator 31 which is mounted to the plate-like member 22 via a pair of pivot posts 32 which hold the pivot point of the latch operator outwardly from the plate-like member 2. Each end 31' of the operator is angled from the pivot point to the connection with the latch bar 28 or 29.

It should be noted from FIGS. 1 and 5 that the latch operator 31 extends below the bushing 19 such that elbow connector 16 connects to the receptacle intermediate the ends of operator 31. Thus when the connector 16 is in its closed circuit position, operator 31 cannot be moved sufficiently to retract the latch bars 28 and 29 from engagement with latch plate 27. An offset spring latch assembly 36 is affixed to the plate-like member 22 intermediate the latch bars 28 and 29 and is positioned such that a spring-loaded latch bar 37 included in the assembly 36 also engages an aperture in latch plate 27. Latch bar 37 is biased toward an engaged position and has an inclined rear surface 38 which acts as a cam surface to allow the latch bar 37 to retract as the plate-like member 22 is moved to its closed position. A pull ring 39 is provided for applying a retracting force to disengage the latch bar 37 from the latch plate 27.

All of the latch mechanisms and connector mechanisms heretofore described, with the exception of bushing 19, are normally located within the forward compartment 12 or on the "front" of plate-like member 22. On the back of plate like member 22 and normally disposed within the central compartment is a fuse mounting assembly 41. The fuse mounting assembly 41 includes a pair of insulators 42 and 43 spaced apart on plate-like member 22. Each insulator 42 or 43 supports a fuse holder 44 and a current bus 46 or 46'. Current bus 46 connects the bushing 19 and associated electrical conductors with the fuse holder 44 and fuse end supported by insulator 42. Current bus 46' is the disconnect bus supported by insulator 43. The disconnect bus 46' extends perpendicularly to plate-like member 22 through an opening in an insulative rear partition wall 47 separating the rear compartment 14 from the central compartment 13. An electrical contact 48 is housed in compartment 14 in cooperative position to engage bus 46' in a closed circuit position.

The opening formed in wall 47 is sufficiently large to allow the disconnect bus 46' to pivot into engagement with contact 48; however the opening is closed in the absence of the disconnect bus 46' by a shutter 49 which is slidably mounted to wall 47 and urged toward a closed position by a spring 51 which is connected to the cabinet 11 or wall 47. The spring 51 is connected to an upper flange 52 on said shutter by a non-conducting rod 53 or flexible member. Mounted to the disconnect bus 46' is a shutter operator 54 such as an elongated rod as shown in FIGS. 2, 3 and 4, which is offset from the disconnect bus 46' such that as the plate-like member 22 pivots toward its closed position the operator 54 precedes the disconnect bus 46' and engages the flange 52 to force the shutter 49 downwardly out of the way of disconnect bus 46'. As may be presumed the partition wall 47 and the shutter 49 as well as the operator 54 and a brace 56 therefor are made of a non-conductive electrically insulative material such as polyglass. The non-conducting rod 53 assures that the spring 51 does not contact the bus 46' in the energized position.

To move the mechanism from the close circuit to open circuit position, the technician must first engage the eye 21 on the elbow connector 16 and disconnect the connector 16. Only then can the latch operator 31 be raised sufficiently to disengage latch bars 29 and 29 from latch plate 27. He must also pull on ring 39 to retract the spring loaded latch bar 37, whereupon the plate-like member 22 carrying the fuse is free to pivot into the forward compartment 11. As the plate-like member 22 pivots, the disconnect bus 46' is lifted from engagement with the contact 48 and the shutter operator 54 releases the shutter 49 thereby closing the opening in wall 47. With the plate-like member 22 in the fully open position as shown in FIG. 3, the technician can visually confirm that the fuse is completely disconnected from the circuit and that he is isolated from the contact 48 in the rear compartment by the partition wall 47 and shutter 49.

While I have shown my invention in one form, it will be obvious to those skilled in the art that it is not so limited but is susceptible of various changes and modifications without departing from the spirit thereof.