Electrical connectors – With unauthorized connection preventer – e.g. – key or...
Reexamination Certificate
2000-01-28
2002-07-02
Abrams, Neil (Department: 2839)
Electrical connectors
With unauthorized connection preventer, e.g., key or...
C439S924200, C439S304000, C070S057000
Reexamination Certificate
active
06413104
ABSTRACT:
FIELD OF INVENTION
The present invention relates generally to a method of and apparatus for locking an electrical plug to a power distribution panel having a sequential coupling guard and precluding removal of an electrical plug from such power distribution panel.
BACKGROUND ART
Power distribution panels employing sequential coupling guards are known in the art. An example is disclosed in U.S. Pat. No. 4,955,821 (hereinafter the '821 patent) entitled “Method For Controlling Connector Insertion Or Extraction Sequence On Power Distribution Panel” to the present inventor and assigned to a common assignee which is hereby incorporated by reference in its entirety into this specification.
FIGS. 1-5
are taken from the '821 patent and represent the prior art. With reference to
FIG. 1
, there is shown a cam ring mechanism including a plurality of cam rings
11
-
15
mounted in an upper and lower channel member
20
and arranged along a common axis
30
best seen in
FIG. 2
which passes through the three and nine o'clock positions of each of the rings. The cam rings
11
-
15
are positioned at the rear of an array of electrical receptacles
21
-
25
: the receptacle
21
may be a ground receptacle, the receptacle
22
may be a neutral receptacle, and the receptacles
23
-
25
may be for three-phase power. The receptacles are the type in which a plug must be twisted or rotated approximately 45° before making a final electrical connection thereto.
Each cam ring
11
-
15
includes an outer cam surface
16
which is generally convex in shape. The cam surface
16
does not extend completely around the cam ring and is subtended by a clearance notch
17
and a locking notch
18
. The clearance notch
17
and the locking notch
18
are generally concave in shape and are dimensioned to mate with the convex cam surface
16
on an adjacent cam ring. The clearance notch
17
is located between the one and two o'clock position on each cam ring and the locking notch
18
is located at the nine o'clock position. Each cam ring includes a pair of tabs
19
which extend toward the center portion of the ring and provide engagement means for turning the cam ring as more fully described below. Rotation of each cam ring is limited by stops
27
.
In
FIG. 1
, each of the rings
11
-
15
is in an original, unrotated position. In
FIG. 2
, the first three rings
11
-
13
have been rotated clockwise as if an electrical connection has been made to the first three receptacles
21
-
23
. The plugs inserted in the receptacles are not shown.
FIG. 3
shows an alternate embodiment of the invention in which each of the receptacles
22
-
25
is positioned behind an aperture
28
in a front panel
29
and access to the apertures
28
is controlled by a cover plate
32
-
35
, respectively. Each of the cover plates
32
-
35
is mechanically coupled to the cam ring adjacent and to the left of the receptacles
22
-
25
; that is, cover
32
is coupled to the cam ring
11
, cover
33
is connected to the cam ring
12
, cover
34
is connected to the cam ring
13
, and cover
35
is connected to the cam ring
14
. The connection between the cam rings and the various covers
32
-
35
is made by a link
37
best seen in
FIGS. 4 and 5
. It will be noted that there is no cover plate over the first receptacle
21
. This is problematic as will be described below.
FIG. 4
shows a side view of the receptacle assembly
21
which comprises a conductive pin
41
and an insulating sleeve
42
which is spaced therefrom. The cover plate
32
which in one position blocks access to the adjacent receptacle
22
is shown rotated to an open position and is connected to the cam ring
11
by the link
37
. The conductive pin
41
and the sleeve
42
are mounted on a support
43
and a coupling tab
44
extends from the rear of the pin
41
for connection to a cable or other conductive element as well known in the art.
A plug
46
comprises an electrical socket
47
and an insulating sheath
48
which are dimensioned to mate with the receptacle
21
. The conductive socket
47
is coupled to a cable connector
50
which may be terminated to an electrical cable as well as known in the art. The forward portion of the insulating sheath
48
includes a pair of slots
49
which are dimensioned to receive the radially extending tabs
19
on the cam ring. The forward portion of the socket
47
includes two L-shaped slots
51
best seen in
FIG. 5
which receive two oppositely directed locking pegs
52
on the rear portion of the pin
41
. When the socket
47
is fully engaged with the pin
41
, the locking pegs
52
are at the bottom of the respective L slots
51
; and the socket
47
may be rotated clockwise to position each of the locking pegs
52
in the foot
53
of the respective slot
51
to lock the socket onto the pin
41
. Rotation of the socket also rotates the cam ring through the engagement of the tabs
19
in the slots
49
. The rotation of the cam ring is limited by the abutment of the tabs
19
against the stops
27
.
Mode Of Operation
The coupling guard controls the sequence of connecting a plurality of plugs to a plurality of receptacles as explained below.
Referring first to
FIG. 1
, the cam ring
11
which surrounds the ground receptacle
21
, may turn either clockwise or counterclockwise since the cam surface
16
is free to turn relative to the locking notch
18
on the cam ring
12
. The cam ring
12
is not free to turn, however, since the locking notch
18
is in an abutting relationship with the cam surface
16
of the cam ring
11
. In a similar way, the locking notch
18
of each of the cam rings
13
-
15
is in abutting relationship with the cam surface
16
of the cam ring to the immediate left. Rotating the cam ring
11
clockwise approximately 45° will abut the tabs
19
against the stops
27
and will position the clearance notch
17
of the cam ring
11
adjacent the cam ring
12
. in this position, the cam ring
12
is free to rotate since the cam surface
16
of the ring
12
will pass through the clearance notch
17
of the cam ring
11
. After the cam ring
12
has been rotated clockwise approximately 45°, the clearance notch
17
of cam ring
12
will be adjacent the cam ring
13
. This will allow the cam ring
13
to be rotated; and in a similar fashion, the cam rings
14
and
15
may likewise be rotated once the cam ring immediately adjacent and to the left has been rotated clockwise to position the clearance notch
17
adjacent the cam ring which is next to be rotated.
In the manner described above, a series of plugs which must be rotated to couple with a series of receptacles can only be connected to the receptacles
21
-
25
in sequence from left to right. Engagement means on the cam rings such as the tabs
19
may be used to interlock with a plug which is inserted into the receptacle and to turn in response to a rotation of the plug. The clockwise rotation of the plug and the cam ring allows the adjacent cam ring to the right to be turned and thus the sequence of connections to be made. Plug and receptacle connectors such as shown in
FIGS. 4 and 5
which require a partial turn or twist in order to make final electrical connection to a receptacle are well known in the art. Such connectors can be used with the apparatus of
FIG. 1
with the result that the several plugs will have to be coupled to the plural receptacles in the predetermined sequence.
The apparatus of
FIG. 1
will also insure that the disconnection of the several plugs is made in the correct sequence. As shown in
FIG. 2
, once the cam rings
12
and
13
have been rotated 45° clockwise, the cam surface
16
of the cam rings
12
and
13
engages the clearance notch
17
of the cam rings
11
and
12
, respectively. As a result, the cam rings
11
and
12
are locked against rotation; and cam ring
13
must be rotated counterclockwise to align the locking notch
18
of the cam ring
13
with the cam ring
12
. Once this alignment has been made, it will be possible to rotate the cam ring
12
counterclockwise to align th
Abrams Neil
Lowe Hauptman & Gilman & Berner LLP
Northrop Grumman Corporation
LandOfFree
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