Electricity: circuit makers and breakers – Interlocking – Between switches and housing
Reexamination Certificate
2002-11-18
2004-03-02
Abrams, Neil (Department: 2839)
Electricity: circuit makers and breakers
Interlocking
Between switches and housing
C200S050120
Reexamination Certificate
active
06700081
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
BACKGROUND OF THE INVENTION
The present invention relates to electrical fuse blocks for mounting in cabinets and having a forwardly-extending, rotary disconnect operator that may engage a handle on the cabinet door when the cabinet door is closed, and in particular to an improvement in such a fuse block that reduces the chance of accidental operation of the disconnect operator when the cabinet door is open.
Referring to
FIG. 1
, a standard fuse block
10
of the prior art may receive fuse cartridges
12
along its front face and may attach at its rear face to the rear wall
14
of a metal cabinet
16
.
Input terminals along the top of the fuse block
10
may receive wires
18
which connect independently to one side of each fuse cartridge
12
, the latter which interconnect wires
18
to wires
20
attached to output terminals along the bottom of the fuse cartridge
12
. The wires
18
, for example, may be connected to a source of three-phase power and the wires
20
, for example, may be connected to a motor or other piece of equipment.
The fuse block
10
may incorporate a disconnect mechanism (not shown) serving to electrically disconnect the wires
18
from the respective fuse cartridges
12
. The disconnect may be controlled by a rotary operator
22
along one side of the fuse block
12
and extending in an orientation perpendicular to the rear wall
14
of the cabinet
16
toward an open face of the cabinet
16
.
The open face of the cabinet may be covered by a door
24
attached by hinges to one side of the cabinet
16
. The door
24
may support a captively mounted rotary handle
26
having an inwardly extending shaft
28
.
Referring now to
FIG. 2
, the handle
26
may include a shaft
28
extending inwardly through an opening in the door
24
and having retaining flanges
30
for retaining it rotatively within that opening.
When the door
24
is closed about the cabinet
16
, the shaft
28
of the handle
26
may engage the outermost end of the rotary operator
22
allowing the rotary operator to be operated by the handle
26
when the door
24
is closed on the cabinet
16
. Specifically, an inwardly facing end of the shaft
28
may include a keyway
32
receiving a rectangular end of the rotary operator
22
and a pin
34
extending perpendicularly through the rotary operator. Turning the handle
26
, turns the rotary operator
22
electrically disconnecting or connecting power to wires
20
.
Referring again to
FIG. 1
, while the handle
26
allows disconnection of power to wires
20
, the door
24
on the cabinet
16
is closed. Once the door
24
is open, power may be inadvertently reconnected by counter rotation of the rotary operator
22
which is how exposed.
BRIEF SUMMARY OF THE INVENTION
The present invention modifies a standard fuse block to allow it to sense the position of the door of the cabinet and lock its disconnect in the open position to prevent inadvertent connection of power when the cabinet door is open. The locking of the disconnect may be manually overridden if it is necessary to reconnect power when the cabinet door is open.
Specifically, the present invention provides a side mounted lockout positioned proximate to the side face of the fuse block and having a sensing arm having a first end positioned near the outer end of the of the fuse block's rotary operator. When the door is closed, the sensing arm is pressed inward by engagement of the outer end rotary operator and the door mounted handle. An operator lock communicates with the sensor arm and the rotary operator to lock rotation of the rotary operator except when the sensing arm is depressed.
Thus, it is one object of the invention to provide a method of locking fuse blocks of this type against inadvertent actuation when the door is open.
It is another object of the invention to provide a locking mechanism that will work with a variety of different cabinet types. Locating the door sensor near the operator, allows the door handle, which necessarily is positioned to engage the rotary operator, to provide the necessary actuation. Modifications to the door or a particular location or orientation of the fuse block within the cabinet are not required so long as the operator of the fuse block properly engages the door handle.
The sensing arm may be a sleeve slidably fitting over the rotary operator.
Thus, it is another object of the invention to provide for a simple sensing mechanism that is fully supported by the sensing arm to be in alignment with the actuating door handle.
The sleeve may include at least one radial extension arm abutting the portion of the door mounted handle when the outer end of the rotary operator is engaged with the portion of the door mounted handle.
Thus, it is another object of the invention to provide a door sensor that works with a variety of different door mounted handles so long as some part of the door handle engages the radial arm.
The radial extension arm may extend over the front face of the fuse block when the rotary operator is rotated to connect power. Conversely, the radial extension arm may extend along the side face of the fuse block and not over the front face when the rotary arm is rotated to disconnect the fuse to the power connections.
Thus it is another object of the invention to provide a visual indication of a connected fuse block, and alternatively, to prevent interference with removal of the fuses by the radial arm when the fuse block is disconnected.
The operator lock may include a collar engaging the rotary operator and having at least one tooth captured by a stop communicating with the sensing arm to be retracted when the sensing arm is depressed inward.
Thus, it is another object of the invention to provide a locking mechanism that may work with existing fuse block designs by engagement of a collar with the normally rectangular shaft of the rotary operator.
The stop may be a slider plate mounted slidably to a support plate fixed with respect to the fuse block, the slider plate sliding along an outwardly extending axis.
It is another object of the invention to provide a locking mechanism that may fit closely adjacent to the fuse block so as not to increase the amount of space required within the cabinet for the fuse block.
The slider plate and mounting plate may have holes sized to receive the shank of a padlock and aligned when the operator is in the position of disconnecting the fuse.
Thus, it is another object of the invention to provide for a positive lockout of the fuse block that cannot be defeated by opening of the cabinet door or manipulating the mechanical operator lock.
These particular objects and advantages may apply to only some embodiments falling within the claims, and thus do not define the scope of the invention.
REFERENCES:
patent: 1404865 (1922-01-01), Kries
patent: 1417920 (1922-05-01), Jessen
patent: 2053997 (1936-09-01), Kriek
patent: 2465079 (1949-03-01), Fitzgerald
Abrams Neil
Gerasimow Alexander M.
Quarles & Brady
Rockwell Automation Technologies Inc.
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