Snap switch

Details Snap switch Snap switch

1999-04-23

2001-09-18

Luebke, Renee (Department: 2833)

Electricity: circuit makers and breakers

Snap

Double snap

C200S439000, C200S533000

Reexamination Certificate

active

06291784

ABSTRACT:

TECHNICAL FIELD
This invention generally relates to electrical switches and more particularly relates to turning indicator switches for motor vehicles.
BACKGROUND OF THE INVENTION
Snap switches are usually provided with a moving, preferably pivoting, contact lever and a switching member which acts upon it by means of spring action. In this case, the switching member is usually moved by means of a plunger sliding in a straight direction.
In order to achieve a sudden switching action, the spring engages first above and then below the longitudinal axis of the pivoting contact lever, depending on the movement of the switching member. Thus, a sudden reversal of the torque acting on the contact lever is attained. A snap switch of this kind is described, for example, in DE-PS 29 28 214. A disadvantage of the snap switch described therein is that the contact force of the contact lever is reduced to zero shortly before the switching process, so that the switching contact is not securely in place just before the switching. That can lead to an increase in the switch resistance shortly before the switching and also increased wear due to arcing and the like.
Additional consideration has been given to increasing the contact force of the contact lever shortly before the switching process instead of trying to reduce it. Due to that, an increasing contact force of the contact on the contact lever is obtained with respect to the fixed contact. This lasts up to the time when the contact lever is switched under a sudden change of direction of the comparatively large contact force, and then sets with large force onto the opposing contact. The contact force decreases somewhat after the end of the plunger movement. A similar switch is described, for example, in DE-PS 39 40 285. This already known switch pertains to a make contact. However, it can also be designed as a break contact or as a changeover switch while retaining the stated advantages.
On the other hand, a disadvantage of the switch according to DE-PS 39 40 285 is that a switching member (
16
) and a contact lever (
33
) are located essentially in the same plane. For that reason, a housing must be chosen long enough that it can hold the two components arranged in succession. In addition, the straight movement of a plunger (
46
) in this switch must be converted into a pivot motion of the switching member (
16
).
Therefore, a change was made, and DE-PS 39 42 925 discloses the switching member in the housing on a straight path extending essentially perpendicularly to the longitudinal direction of the contact lever. A disadvantage of this known switch, however, is that its housing is integrated as a single piece into a support element, i.e., the housing of the switch and also the support element itself are cast as a single piece of plastic. When using several switches, the switch housing can be assembled only with the components of the switch in the direction of the support element, that is, perpendicular to the plane of the support element. But assembling parallel to the plane of movement of the contact lever is comparatively difficult and can only be practically implemented by manual means. This is because individual components of the switch must necessarily undercut each other in the plane of movement of the contact lever, so that in the direction of installation they can only be inserted into the switch one after the other. In addition, the installation surface bounded by the side walls of the switch is comparatively small, so that only a comparatively small installation window is available for assembling.
SUMMARY OF THE INVENTION
According to the present invention, a snap switch comprises a housing formed by a first and a second housing parts, between which parts first and second connector elements are fixed. The second housing part has chambers and wall recesses open toward the first housing part to install the connector elements and other components of the switch in an open direction of the chambers and recesses. A contact lever movable in a plane of motion between an idle and a working positions is mounted so as to pivot in the housing and connected to the first connector element. Contacted by the contact lever in one of its end positions is a fixed contact rigidly attached in the housing and connected to the second connector element A switching member bears a wedge profile defining an apex, and it is adapted to be guided along a first path extending essentially perpendicular to the contact lever. Thus, the switching member, as the apex passes past the contact lever, forces the contact lever to move from the idle position to the working position.
The switching member bears a switching slider. They both are made of plastic, and the switching slider is inserted into the switching member The switching slider comprises a head portion and a leg portion and is inserted into the switching member with its leg portion that has a square cross-section to prevent its rotation within the switching member. A restoring spring braced against the housing is located in a recess of the switching member and biases the switching member to its rest position.
The head portion of the switching slider is imparted the form of two support surfaces, which face the contact lever and collectively form the wedge profile meeting the contact lever. The support surfaces may be covered with an insulating material or a heat-dissipating material.
The leg portion of the switching slider is made hollow to accommodate a switching spring pressing the switching slider against the contact lever. The spring is braced against the switching member and is guided by a guiding pin.
One end of the switching member, which is located opposite from the restoring spring, projects in the form of an actuating lug out of the recess of the housing. The actuating lug is equipped with a chamfer inclined with respect to the first path of the switching member so that the switching member can be actuated both by an actuating element moving in parallel to the first path, as well as by an actuating element moving transverse to the first path.


REFERENCES:
patent: 1087251 (1914-02-01), Meaher
patent: 3042764 (1962-07-01), Hermle
patent: 3639714 (1972-02-01), Fujimoto et al.
patent: 4275279 (1981-06-01), Wagatsuma et al.
patent: 4788388 (1988-11-01), Burch et al.
patent: 5794764 (1998-08-01), Hirose et al.
patent: 2928214 (1980-01-01), None
patent: 3336877 (1985-05-01), None
patent: 3940285 (1991-06-01), None
patent: 3942925 (1991-06-01), None

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