Electricity: circuit makers and breakers – Multiple circuit control – Pivoted contact
Reexamination Certificate
1999-03-16
2001-03-27
Luebke, Renee (Department: 2833)
Electricity: circuit makers and breakers
Multiple circuit control
Pivoted contact
C200S569000
Reexamination Certificate
active
06207908
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an improved mode switch.
A typical conventional mode switch is shown in
FIGS. 25
,
26
and
27
. The conventional mode switch includes arc stationary contacts
102
with respective predetermined lengths exposed and formed in the form of plural concentric circles on the upper surface of a base
101
, and a single comb-like movable contact spring piece (generally called brush)
104
attached on the lower surface of a disc rotor
103
and having plural contact spring pieces arranged in parallel with one ends acting as contacts. The center shaft
105
on the base
101
is rotatably fitted to the center hole
106
in the rotor
103
. The contacts of the movable contact spring piece
104
sliding over the upper surface of the base
101
in a contact state are slidably and sequentially contacted to the stationary contacts
102
(or are turned ON) by rotating the rotor
103
. When the contacts of the movable contact spring pieces
104
are opened from the stationary contacts
102
(or come to the positions where the stationary contacts
102
are not exposed), the mode switch is turned OFF.
Generally, in order to rotatably mount the rotor
103
to the base
101
without dropping, the mounting cover
111
for covering the whole surface of the rotor
103
is attached to the base
101
by inserting the engaging protrusions
112
of the base
101
into the engaging holes
111
a
in the right and left side plates.
Since the movable contact spring piece
104
always slides under pressure on the inner surface of the base
101
(on the insulating surface and stationary contacts), together with the rotor
103
rotated, grease is always applied on the movable contact spring piece
104
, so that the rotation of the rotor
103
, that is, the sliding of the movable contact spring piece
104
although always in contact with the inner surface of the base is always maintained smooth.
A loss of such smoothness causes erroneous signal reception or noise mixture.
However, the use of grease leads to the following drawbacks:
(1) A grease film formed on the contact surface of a contact may interfere with good electrical conduction of the contact.
(2) Particles or dusts caused by the friction during the sliding operation contaminate the grease and degrades the lubrication or conduction.
The grease may solidify or be degraded during a long service period, thus deteriorating the lubrication, conduction, or the like.
As described above, since the metal movable contact spring piece
104
directly slides over the metal stationary contacts
102
under pressure, metal particles produced in the sliding and polishing operation tend to cause a contact failure. Thus, variations in contact state at different portions result in noises. For that reason, a mode switch that does not use any grease and does not have its contacts slidably contacted to each other has been long desired.
In the mode switch, the stationary contacts
102
on the base
101
must be always juxtaposed with the contacts of the movable contact spring piece
104
on the lower surface of the rotor
103
with high precision with no variations in mode switches. In order to realize such requirements, the fitting accuracy must be set between the center shaft
105
of the base
101
and the center hole
106
of the rotor
103
must be fit together as accurately as possible and set a gap between the outer diameter of the shaft and the inner diameter of the shaft hole as small as possible. Since the rotor must be lightly rotated by a very small rotational force, the shaft is loosely fitted to the gap which allows sufficient mobility. The base and the rotor are a molded pieces made of general-purpose plastic (not special plastic for expense precision devices). Hence, variations in these molded products may cause irregular rotation of the rotor.
Moreover, in the conventional mode switch, in order to prevent the irregular rotation, the resilient recovery force of the movable contact spring piece presses the upper surface of the rotor against the lower surface of a mounting cover which covers the whole surface of the rotor and which prevents the rotor from being dropped off, thus stopping the moving of the rotor. However, the mounting covers, which are formed through a sheet metal shaping process under pressure, varies in their dimensions means for attaching the mounting cover to the base, for example, the engagement between the mounting cover engaging hole and the engaging protrusion on the base, requires high precision in their dimensions. Hence, variations in spacing in each switch make it difficult to improve the switching performance.
In the conventional mode switch, the rotor must be attached with a different mounting cover. This makes it difficult to reduce the number of constituent components for a mode switch the fabrication steps and the manufacturing costs, and also to improve the productivity.
SUMMARY OF THE INVENTION
An objective of the present invention is to provide a mode switch that does not require any grease and does not have its contacts slidably contacting to each other.
The objective of the present invention is achieved by a mode switch comprising a base, a rotor, a contact spring piece plate, and an actuator plate.
More specifically, the rotor is made of an insulation disc plate, a hollow center shaft protruding at the center of the lower surface of the insulation disk plate, a circumferential side plate protruding on the outer circumferential fringe of the insulation disc plate, engaging rims protruding from the outer circumferential fringe, and a predetermined number of arc protruding stripes or protrusions of a predetermined length arranged on the insulation disc plate and at predetermined positions on a predetermined number of assumed concentric circles centered with respect to the hollow center shaft.
The base is made of a circular insulation substrate, a center shaft protruding from the center of an upper surface of the circular insulation substrate to be fitted into the hollow center shaft of the rotor, engaging pieces planted along outer circumference of the engaging rims of the insulation substrate at angles set on an assumed concentric circle, engaging pieces having edges acting as engaging pawls, and circumference protruding stripes fitted to the circumferential side plate of the rotor with respect to the center shaft.
Guide pillars face the concentric circles on the rotor imaginarily drawn around the center shaft on the rotor and being provided adjacent to the concentric circles. The guide pillars have guide grooves or holes respectively positioned along the concentric circles, stationary contacts being exposed and formed on the base at positions adjacent to the concentric circles, the stationary contacts respectively extending to terminals outside the insulation substrate, the guide pillars being provided at positions bilaterally symmetrical to the center shaft to fit the contact spring piece plate and the actuator plate.
The contact spring piece plate has a predetermined number of strip-like contact spring pieces integrally and protrusively formed on the lower sides of right plates and left plates of sectoral metal spring pieces, the contact spring plate having one ends acting as movable contacts, each of the right plates and the left plates having mounting holes for fitting the pillars of the base, and movable contacts of the contact spring pieces being positioned so as to be relatively spaced above the stationary contacts on the base while the contact spring piece plate is attached to the base.
The actuator plate is formed of an insulation plate of the substantially same shape as the contact spring piece plate, and having actuators positioned so as to respectively face with the contact spring pieces of the contact spring piece plate; the actuator plate having insertion holes positioned so as to face the mounting holes in the contact spring piece plate. An angled-top-like actuators are integrally formed on the ends of strip-like spring piece integrally protruding f
Luebke Renee
Mitsuku Denki Kogyo K.K.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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