Switchgear enclosure with improved electronic control access door and lock

A switchgear apparatus comprising a switch mechanism, electrical controls for the switch mechanism, a weatherproof door movable between a closed position and an open position for respectively preventing and affording access to the electrical controls, a housing enclosing the switch mechanism and the electrical controls and including a second door for affording access to the weatherproof door, a third door movable between an open position and a closed position, an operating handle movable between an open position and a closed position, the operating handle being locatable in the open position only when the third door is in the open position, and a mechanism for releasably retaining the second door in the closed position, the mechanism being releasable only when the operating handle is in the open position.

BACKGROUND OF THE INVENTION 
The invention relates to switchgear apparatus, and more particularly to 
access doors and locks for electronic controls of switchgear apparatus. 
Industry standards require that access doors for switchgear electronic 
controls be locked. Typically, pentahead bolts are used to secure access 
doors, and padlocks are used to prevent access to the pentahead bolts. 
This requires a separate pocket to accommodate a padlock or pentahead 
bolt. 
Furthermore, access doors for switchgear electronic controls are usually 
weatherproof in order to prevent damage to the electronic controls. Access 
doors are usually weatherproofed by providing some type of seal around the 
door. Unfortunately, unauthorized attempts to force access doors open 
usually result in damage to the seal and a loss of weatherproofing. 
SUMMARY OF THE INVENTION 
The invention provides a switchgear enclosure in which the lock mechanism 
for the electronic control access door is located in a switch operating 
handle box. Access to the lock mechanism is obtained by opening the 
operating handle door and moving the operating handle to the open 
position. 
More particularly, the invention provides a switchgear apparatus comprising 
a housing or enclosure enclosing a switch or interrupter mechanism and the 
electronic control means therefor. The housing includes an access door 
movable between a closed position and an open position for respectively 
preventing and affording access to the electronic control means. The 
housing also includes an operating handle movable between an open position 
and a closed position, and an operating handle door movable between an 
open position and a closed position for respectively affording and 
preventing access to the operating handle. The operating handle is 
locatable in the open position only when the operating handle door is 
open. The operating handle door is locked by a conventional pentahead bolt 
and padlock arrangement. 
The apparatus further comprises a lock mechanism including a bolt axially 
movable between a locked position wherein the bolt prevents opening of the 
access door and an unlocked position wherein the bolt permits opening of 
the access door, and means for biasing the bolt toward the locked 
position. The operating handle is pivotally mounted on the bolt for 
movement between the open position and the closed position, and the 
operating handle is connected to the bolt for movement therewith along the 
axis of the bolt. The lock mechanism further includes means for preventing 
movement of the operating handle to move the bolt to the unlocked position 
when the operating handle is in the closed position. This means preferably 
includes a clip mounted on the housing and engaging the operating handle 
when the operating handle is in the closed position. 
In the preferred embodiment, the apparatus further comprises a weatherproof 
inner door for alternatively preventing and affording access to the 
electronic control means, and the above-mentioned access door 
alternatively affords and prevents access to the weatherproof door. The 
combination of the access door and the inner door provides 
tamper-resistant means for preventing access to the electrical controls. 
Preferably, the apparatus comprises a control unit mounted in the housing 
and including the electronic controls and the weatherproof door. 
Other features and advantages of the invention will become apparent to 
those skilled in the art upon review of the following detailed 
description, claims and drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
A switchgear apparatus 10 embodying the invention is illustrated in the 
drawings. The apparatus 10 comprises at least one switch or interrupter 
mechanism 12, and preferably a plurality of such mechanisms 12, some of 
which are shown in dotted lines in FIG. 1. The apparatus 10 also comprises 
a control unit 14 including electrical control means for the switch 
mechanisms 12. Such control means are known in the art and need not be 
described in greater detail. 
The apparatus 10 also comprises (see FIGS. 1 and 3) a weatherproof door 16 
movable between a closed position (shown in solid lines) and an open 
position (shown in dotted lines) for respectively preventing and affording 
access to the electrical control means. As shown in FIG. 3, the 
weatherproof door 16 includes seal means 18 for preventing exposure of the 
electrical control means. Preferably, the door 16 is an integral part of 
the control unit 14. Stop means (not shown) is provided for preventing 
movement of the door 16 beyond the open position. 
The apparatus 10 also comprises a housing 20 enclosing the switch 
mechanisms 12 and the control unit 14. The housing 20 includes (see FIGS. 
1 and 3) an outer access door 22 movable between an open position (shown 
in FIG. 1) and a closed position (shown in FIG. 3) for respectively 
affording and preventing access to the weatherproof door 16. Preferably, 
the door 22 is spring loaded to the open position and has a continuous 
hinge (not shown). Also, stop means (not shown) is provided for preventing 
movement of the door 22 beyond the open position. 
The apparatus 10 further comprises (see FIGS. 2-4) means for releasably 
retaining the access door 22 in the closed position. While various 
suitable retaining means can be employed, in the preferred embodiment, the 
retaining means includes a bolt 24 extending along an axis 26 and being 
slidably supported by the housing 20. As shown in FIGS. 2-4, the bolt 24 
is slidably supported by a bushing 28 which in turn is supported by the 
housing 20. The bolt 24 is also supported by a mounting bracket 30 fixedly 
connected to the housing 20. As shown in FIG. 7, the mounting bracket 30 
includes a generally horizontal portion 32 connected to the housing 20 by 
suitable means such as bolts 34, and a pair of spaced apart, generally 
vertical portions 36 extending downwardly from the horizontal portion 32. 
Each of the vertical portions 36 includes an integral, forwardly extending 
portion having therein an aperture 38 centered on the bolt axis 26. The 
bolt 24 extends through the apertures 38 for axial and pivotal movement of 
the bolt 24 relative to the mounting bracket 30. As shown in FIG. 4, the 
right aperture 38 has therein a bushing 40 which slidably and rotatably 
supports the bolt 24. 
The bolt 24 is axially movable in a first direction (to the right in FIGS. 
2-4) to a locked position (shown in FIG. 3) wherein the bolt 24 extends 
through an aperture 42 in the door 22, and the bolt 24 is movable in an 
opposite second direction (to the left in FIGS. 2-4) to an unlocked 
position (shown in FIG. 4) wherein the bolt 24 is withdrawn from the 
aperture 42. 
The retaining means also includes means for biasing the bolt 24 in the 
first direction or to the locked position. While various suitable biasing 
means can be used, in the preferred embodiment, the biasing means includes 
a spring 44. The manner in which the spring 44 biases the bolt 24 to the 
locked position is described hereinafter. 
It is noted that the combination of the locked outer door 22 and the inner 
door 16 provides tamper-resistant means for preventing access to the 
electrical control means. 
The apparatus 10 also comprises an operating handle recess 46 located in 
the housing 20. The recess 46 has therein a shaft 47 for operating the 
switch mechanisms 12 and a tool (not shown) for rotating the shaft 47. The 
apparatus 10 also comprises an operating handle door 48 movable between an 
open position (shown in dotted lines in FIGS. 1 and 5) and a closed 
position (shown in solid lines in FIGS. 1 and 5) for respectively 
affording and preventing access to the operating handle recess 46. 
Preferably, the door 48 is located adjacent the door 22 and is an integral 
part of the housing 20. As shown in FIGS. 5 and 9, a pentahead bolt 49 is 
provided for locking the door 48, i.e., for releasably retaining the door 
48 in the closed position. A padlock (not shown) is provided for 
preventing access to the bolt 49. This arrangement is conventional. 
The apparatus 10 also comprises an operating handle 50 located in the 
operating handle recess 46. Referring to the operating handle 50 in its 
closed position, or as shown in FIG. 7, the operating handle 50 includes a 
generally horizontal portion 52, and a downwardly extending operator 
actuatable portion 54. The operating handle 50 further includes an 
upwardly extending projection 56 including an enlarged upper end. The 
reason for the projection 56 is explained hereinafter. The operating 
handle 50 also includes a pair of spaced apart, upwardly extending 
portions 58 having therein respective apertures 60 pivotally receiving the 
bolt 24. 
The operating handle 50 is mounted on the bolt 24 for pivotal movement 
between an open position (shown in solid lines in FIG. 6) and a closed 
position (shown in solid lines in FIG. 5). Also, the operating handle 50 
is connected to the bolt 24 for movement therewith along the axis 26 of 
the bolt 24. While various suitable means can be used for connecting the 
operating handle 50 to the bolt 24, in the illustrated construction, such 
means includes a pair of snap rings 62 secured to the bolt 24 and located 
on opposite sides of the left portion 58 of the handle 50 so that the bolt 
24 is not axially movable relative to the operating handle 50. As shown in 
FIGS. 3 and 4, the mounting bracket 30 is located in the recess 46 and the 
spring 44 is located between the left portion 36 of the mounting bracket 
30 and the right portion 58 of the operating handle 50, so that the spring 
44 biases the operating handle 50, and thus the bolt 24, to the right 
relative to the mounting bracket 30 and to the housing 20. 
The retaining means is releasable only when the door 48 is in the open 
position and the operating handle 50 is in the open position. 
As shown in FIGS. 5 and 6, the operating handle door 48 prevents movement 
of the operating handle 50 to the open position when the door 48 is in the 
closed position. Therefore, the operating handle 50 is locatable in the 
open position only when the operating handle door 48 is in the open 
position. 
Because the operating handle 50 is connected to the bolt 24 for axial 
movement therewith, movement of the operating handle 50 toward the 
unlocked position causes movement of the bolt 24 toward the unlocked 
position. The retaining means preferably also includes means for 
preventing movement of the operating handle 50 toward the unlocked 
position when the operating handle 50 is in the closed position. While 
various suitable preventing means can be used, in the illustrated 
construction, such means includes clip means 64 mounted on the housing 20 
for engaging the operating handle 50 when it is in the closed position. As 
shown in the drawings, the clip means 64 includes a clip 66 mounted on the 
underside of the mounting bracket 30 by suitable means such as a fastener 
68. The clip 66 is aligned with the upwardly extending projection 56 on 
the operating handle 50 so that the clip 66 receives the projection 56 and 
thereby prevents movement of the operating handle 50 axially of the bolt 
24 when the operating handle 50 is in the closed position. When the 
operating handle 50 is moved from the closed position to the open 
position, the projection 56 moves out of engagement with the clip 66 and 
the operating handle 50 and bolt 24 can be moved along the axis 26 of the 
bolt 24. 
Thus, in order to unlock the access door 22, the operator unlocks and opens 
the operating handle door 48, pivots the operating handle 50 to the open 
position, and moves the operating handle 50 to the left. Movement of the 
operating handle 50 to the left causes common movement of the bolt 24 and 
withdraws the bolt 24 from the aperture 42 in the access door 22, thereby 
permitting opening of the access door 22. Once the access door 22 is open, 
the weatherproof inner door 16 can be opened. 
Because the access door 22 can be opened only after the door 48 is opened, 
the pentahead bolt 49, which releasably retains the door 48 in the closed 
position, constitutes single, exteriorly accessible means for releasably 
retaining the door 22 in the closed position and for releasably retaining 
the door 48 in the closed position. 
Various features of the invention are set forth in the following claims.