Electricity: circuit makers and breakers – Solid contact – Rocking actuator
Reexamination Certificate
2000-07-24
2002-10-01
Scott, J. R. (Department: 2832)
Electricity: circuit makers and breakers
Solid contact
Rocking actuator
C200S244000, C200S339000, C200S437000
Reexamination Certificate
active
06459060
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to electric rocker switches, and more particularly, to switches including a gull wing shaped rocking contact having upper actuating surfaces and lower centering and pivoting surfaces.
BACKGROUND
Rocker actuated electrical switches are well known in the art and numerous designs thereof may be found in commerce. For example, as shown in
FIG. 1
, a switch
10
is disclosed in U.S. Pat. No. 4,203,017. The switch
10
comprises a rocking actuator
12
pivotally mounted on a pivot
14
. A spring follower guide
18
is molded integrally with the rocking actuator
12
and extends downwardly therefrom. The spring follower
20
is reciprocally mounted in a cylindrical bore
22
in the spring follower guide
18
, and a compression spring
24
is compressed between the top
26
of the bore and the bottom
28
of a counterbore
30
in the spring follower
20
.
The compression spring
24
biases the spring follower
20
downwardly, in a direction to eject it from the spring follower bore
22
were it not restrained from such ejection. The spring follower
20
has a blunt point end portion
50
that presses against a rounded V-shaped portion
52
of a rocking contact
54
. The V-shaped portion
52
is formed by a curved central part of a rocking contact
54
lying between and joining two upstanding, diverging portions
56
,
58
of the rocking contact
54
. Beyond the diverging portions, the rocking contact
54
bends downward, then outward at its respective ends to form contacts
74
,
76
. The contacts
74
,
76
match respectively with side terminals
70
,
72
. The contacts
74
,
76
and side terminals
70
,
72
collectively form circuit making and breaking surfaces.
A known problem with such rocker switches
10
is the tendency of the rocking contact
54
to lose its centered rest position with respect to its supporting elements. There is a tendency for the rocking contact
54
to slide laterally or rotate angularly with respect to its support as it tilts from side to side. This adversely affects the ability of the contacts
74
,
76
to make a clean break with the side terminals
70
,
72
. This sliding action can ultimately lead to switch failure by allowing the V-shaped portion
52
to come to rest away from its centered position, preventing one of the contacts
74
,
76
from adequately breaking contact with its respective side terminal
70
,
72
.
To prevent this off-center sliding of the rocking contact
54
, prior art devices have used various supporting and pivoting elements. As shown in
FIG. 2
, the rocking contact
54
has an integral rectangular conductive bearing plate
80
that rests in rectangular notches
82
,
84
in the top edges of a pair of spaced apart parallel side walls
86
,
88
of a center terminal
78
. Ideally, the placement of the rectangular plate
80
in the notches
82
,
84
limits the lateral movement of the rocking contact
54
. However, lateral movement is only limited if the plate fits precisely within the notches
82
,
84
. This prerequisite requires a high degree of manufacturing accuracy. Accordingly, the tolerance for manufacturing flaws is low. If there are imperfections, as is common in the course of manufacturing, the rocking contact will still be able to shift laterally.
Additionally, the use of the rectangular plate
80
does not restrain the axis of angular rotation of the rocking contact
54
during switch operation. Although the plate
80
prevents lateral movement, the rocking contact
54
can still rotate and translate such that its axis of angular orientation is off-center. Depending on the severity of this movement, the problem can cause the switch
10
to fail by biasing the switch
10
in the direction of one of the two contacts
74
,
76
. This affects the ability of the rocking contact
54
to make a clean break with the side terminal
72
,
74
toward which it is biased. This may also affect the ability of the other contact to reach the side terminal
72
,
74
on the opposite side. Accordingly, it is desirable to minimize both the lateral movement of the rocking contact
54
and movement of the axis of angular rotation and during the operation of the rocker switch
10
.
Another disadvantage of known rocker switches is that, generally, the rotation angle of the rocking actuator
12
is in the range of 15 to 30 degrees. In modern applications, it is often ergonomically desirable to limit the angle of actuator rotation to under 10 degrees, and preferably, as low as 7 degrees. The problem with limiting the rotation angle of the rocking actuator
12
is that the motion of the spring follower
18
is likewise limited. If the spring follower
18
does not move sufficiently up the diverging portions
56
,
58
of the rocking contact
54
, it will not be able to exert enough force to cause one of the contacts
74
,
76
to reach its respective side terminal
70
,
72
. Accordingly, it is desirable to limit the angle of the rocking actuator rotation while ensuring that sufficient force will be applied by the follower to enable the contact elements to make contact with the side terminals
70
,
72
.
There is, therefore, a need for a rocker switch in which the rocking contact and its supporting elements insure a reliable return of the contact to a centered rest position and which may be operated with a relatively low rotation angle of the rocking actuator. Therefore, it is an objective of the present invention to provide for a rocker switch that improves upon conventional designs.
SUMMARY OF THE INVENTION
To accomplish the above and other objectives, the present invention provides for an improved electric rocker switch. In a presently preferred embodiment, the present invention provides for an electric rocker switch having a gull wing shaped rocking contact. The rocking contact pivots on a pair of upright blades of a center terminal. At least one centering protrusion disposed on a portion of a lower surface of the rocking contact rests between the upright blades when the rocking contact is in a centered position, which prevents lateral movement of the rocking contact beyond limits of the upright blades. First and second rocker contacts are located on opposite sides of the rocking contact. The first and second rocker contacts face first and second fixed contacts, respectively, such that the first rocker contact touches the first fixed contact when the rocking contact rocks to one side, and the second rocker contact touches the second fixed contact when the rocking contact rocks to the other side. Positioning surfaces are disposed on the lower surface of the rocking contact adjacent to the centering protrusion. The positioning surfaces and top inside edges of the upright blades serve as pivots for the rocking contact as it tilts from side to side.
Other features and advantages of the present invention will become readily apparent to those skilled in this art from the following detailed description, wherein this and other presently preferred embodiments of the invention are shown and described by way of illustration of the best mode completed of carrying out the invention. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the invention. Accordingly the drawings and description are to be regarded as illustrative in nature and not as restrictive.
REFERENCES:
patent: 2478564 (1949-08-01), Bordelon
patent: 3329784 (1967-07-01), Rogero
patent: 3454733 (1969-07-01), Sanford et al.
patent: 4203017 (1980-05-01), Lee
patent: 4335287 (1982-06-01), Aschenbach et al.
patent: 4524253 (1985-06-01), Sorenson
patent: 4978823 (1990-12-01), Sato et al.
patent: 5158172 (1992-10-01), Roeser et al.
patent: 5293507 (1994-03-01), Hayakawa
Float Kenneth W.
Judco Manufacturing, Incorporated
Scott J. R.
LandOfFree
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