Patent Application
20050210632
This application relates to a dimmer switch knob, wherein an intermediate member, or insert, is connected to be driven by an outer knob through a non-cylindrical engagement surface.
Dimmer switches are known to control a light level. As known, a dimmer switch typically includes a knob that may be turned to change a light level from a lower to a higher level. Typically, a dimmer switch includes a shaft that is turned by the knob, and which functions to change the light level.
It is often the case that one would like to have some particular appearance to light switches, etc. As an example, a homeowner may wish that a switch on a wood paneled wall have a wood grain appearance. There are dimmer switch knob designs that can be utilized to provide these varying appearances. One problem with providing a dimmer switch of a particular appearance, is that the connection to the shaft varies across the marketplace. As an example, there are three main shaft designs/sizes currently in the marketplace. Thus, to provide complete choice for, as an example, ten different appearances, there would need to be as many as thirty different knobs.
To reduce this inventory requirement, so-called universal dimmer switches are known wherein separate intermediate members are provided with the knob. A particular intermediate member is selected to correspond to the shaft design on the dimmer switch where the universal knob is to be utilized. The knob is then placed over this intermediate member.
One weakness of the existing design is that the intermediate member has had a cylindrical outer periphery that frictionally engages a cylindrical inner periphery of the knob. At times, and in particular at the extreme ends of travel, the knob has sometimes slipped relative to the intermediate member. This is undesirable.
In a disclosed embodiment of this invention, a dimmer switch knob has a non-cylindrical inner peripheral bore on a rear side. The knob preferably has a particular appearance to be selected as desired based upon an interior design of the building that is to receive the dimmer switch.
The non-cylindrical bore in the knob mates with a non-cylindrical shape from the intermediate member. In this manner, the knob is less likely to slip relative to the intermediate member. In a preferred embodiment, there are a plurality of lobes extending from one of the knobs or intermediate member, that fit into notches in the other. The lobes are preferably formed on the intermediate member with the notches on the knob.
In a preferred arrangement, a plurality of the intermediate members are sold as a kit with the knob. Thus, a user may select the appropriate intermediate member and insert it onto the shaft, and connect the knob to the intermediate member.
The intermediate member preferably has three lobes creating an A-shape with an apex lobe designed to be more rigid than either lobe on the legs. To this end, the apex may be somewhat thicker, or strengthened in some other fashion relative to the legs. Thus, the apex is less likely to slip, and would be better able to resist any forces tending to cause it to slip.
The legs, in a relaxed position, are preferably spaced from each other by an angle that is different than the angle separating the corresponding notches. Thus, when the lobes associated with the legs are received in their respective notches, there is a pre-tension in the legs tending to cause the legs to move away from each other, and resist slippage of their lobes in the notches.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
A universal dimmer switch knob 20 is shown in
An intermediate member 30 connects the knob 20 to a central shaft 31. As known, shaft 31 is connected to a dimmer switch mechanism. Rotation of the knob 20 causes intermediate member 30 to in turn rotate shaft 31, and change the light level provided by the dimmer switch.
The intermediate member 30 also has a non-cylindrical shape, and one that is tailored to match the inner periphery of bore 26 and notches 28 and 29. The intermediate member 30 is generally A-shaped. A central apex lobe 32 extends into notch 28 while leg lobes 34 extend into notches 29. As can be appreciated, the apex lobe 32 is of a greater stiffness than the leg lobes 34.
A central web 36 is formed in the apex 32. A central portion 37 of the intermediate member 30 includes a toothed inner peripheral bore 39 that mates with teeth on the outer periphery of shaft 31. While many of the known dimmer switch styles have a toothed mating connection, other non-cylindrical shapes also exist to connect the internal shaft to the intermediate member. See, for example, the connection shown in element 40 in
Preferably, the notches 29 and notch 28 are spaced from each by an angle A. An angle B is defined between the leg lobes 34 and is preferably greater than angle A between the notches 29.
Angle B, as discussed within this application, is actually bigger than that illustrated in
In a preferred embodiment, the angle B is greater than the angle A by 5° to 10°. In one actual example, the angle B was greater than the angle A by 7°, with angle A 120° and angle B 127°.
The dimmer switch knob 20 is preferably sold as a kit such as shown in
As shown in
As shown in
The present invention is better able to resist slippage by a combination of friction and spring tension to connect the intermediate member to the outer knob.
Although preferred embodiments of this invention have been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.
