Electric switches often must be operated in low light environments and are therefore frequently back-lit or otherwise illuminated. Many switches also have illuminated graphics, words, or other symbols to identify their functions. For example, switches used to control the lights in an automobile are often illuminated and/or have illuminated symbols to identify their functions.
Symbols on pushbutton switches and similar switches are relatively easy to illuminate because the faces on which the symbols are applied don't move much relative to their back lights when they are operated. However, symbols on thumbwheel switches and other types of switches that rotate are more difficult to illuminate because the surfaces on which the symbols are applied move significantly relative to their back lights when the switches are operated.
The present invention solves the above-described problems and provides a distinct advance in the art of illuminated switch assemblies. More particularly, the present invention provides an illuminated thumbwheel switch assembly or other rotary switch that more effectively illuminates a graphic, word, or other symbol on the switch over the entire range of motion of the switch.
An embodiment of the switch assembly comprises a circuit board; a light source mounted on the circuit board; a thumbwheel knob or similar knob rotatably mounted on the circuit board; a transparent surface on which a graphic, word, or other symbol is applied or formed; and a light guide for directing light from the light source to the transparent surface to illuminate the symbol. In one embodiment, the light guide is mounted inside the knob, the transparent surface is a transparent window formed on the light guide, and the knob includes an opening through which the transparent window extends.
The switch assembly may also comprise a pair of electrical contacts printed on or otherwise applied to the circuit board; an electrical conductor configured to contact and move relative to the contacts; and a rack and pinion assembly for moving the conductor relative to the contacts when the knob is rotated. An embodiment of the rack and pinion assembly comprises a rack coupled with the electrical conductor; and a pinion coupled with the light guide and operable to move the rack and the electrical conductor when the thumbwheel knob is rotated. The pinion may be integrally formed with the light guide, and the rack includes an opening for passing light from the light source to the light guide. The rack and pinion assembly advantageously translates rotational motion of the knob into linear motion of the conductor on the contact pads while simultaneously providing a constant distance from the light source to the symbol.
The switch assembly may further comprise a detent mechanism for providing tactile feedback when the thumbwheel knob is rotated. In some embodiments, the switch assembly may be integrated with other switch elements for selecting and controlling one or more lights or other electrical devices in an automobile.
This summary is provided to introduce a selection of concepts in a simplified form that are further described in the detailed description below. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Other aspects and advantages of the present invention will be apparent from the following detailed description of the embodiments and the accompanying drawing figures.
Embodiments of the present invention are described in detail below with reference to the attached drawing figures, wherein:
The drawing figures do not limit the present invention to the specific embodiments disclosed and described herein. The drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the invention.
The following detailed description of embodiments of the invention references the accompanying drawings. The embodiments are intended to describe aspects of the invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the scope of the claims. The following detailed description is, therefore, not to be taken in a limiting sense. The scope of the present invention is defined only by the appended claims, along with the full scope of equivalents to which such claims are entitled.
In this description, references to “one embodiment”, “an embodiment”, or “embodiments” mean that the feature or features being referred to are included in at least one embodiment of the technology. Separate references to “one embodiment”, “an embodiment”, or “embodiments” in this description do not necessarily refer to the same embodiment and are also not mutually exclusive unless so stated and/or except as will be readily apparent to those skilled in the art from the description. For example, a feature, structure, act, etc. described in one embodiment may also be included in other embodiments, but is not necessarily included. Thus, the present technology can include a variety of combinations and/or integrations of the embodiments described herein.
Turning now to the drawing figures, and particularly
The circuit board 12 is mostly conventional and will not be described in detail herein. Among other components, the circuit board 12 includes a pair of spaced-apart contact pads 20, 22 or other electrical contacts best illustrated in
As best shown in
The circuit board 12 may also include contacts and other electronic components for the rotary switch and other components not relevant to the present invention. The particular construction and configuration of the circuit board 12 as well as the components attached thereto is not critical to the invention and may be changed without affecting the scope of the invention.
As mentioned above, the rotary switch 14 may be used to select or otherwise control lights that may then be dimmed by the thumbwheel switch assembly 16. As with the circuit board 12, the particular construction and operation of the rotary switch 14 is not critical to the invention and may be changed without affecting the scope of the invention.
The thumbwheel switch assembly 16 may be integrated in the electrical switch 10 described above or another switch. Alternatively, the thumbwheel switch assembly 16 may be a stand-alone switch.
An embodiment of the thumbwheel switch assembly 16 is best illustrated in
An embodiment of the carrier 28 may be in the general shape of an open ended hollow rectangular cube and includes a number of pegs 38 or legs for insertion into corresponding holes 40 in the circuit board 12. The sidewalls of the carrier include a pair of spaced-apart, aligned holes 42 for receiving a shaft 44 as described below.
The thumbwheel knob 30 serves as a user interface that may be rotated to dim a light or provide a variable electrical signal to any electrical device as described below. An embodiment of the knob 30 is generally semi-cylindrical in shape and includes a number of alternating ridges and depressions for improving its grip. The knob 30 also includes an opening 46 on its outermost surface for receiving a portion of the light guide 32 as described below. A keyed passageway 48 extends through the center of the knob 30 for receiving the shaft 44 to rotatably mount the knob on the carrier.
The light guide 32 is provided for guiding or directing light from the light source 26 to the thumbwheel knob 30. In one embodiment, the light guide 32 fits within the thumbwheel knob 30 and includes an open bottom for receiving light from the light source and a transparent window 50 on which letters, numbers, words, graphics, or other symbols 52 are applied or formed. In one embodiment, a universal symbol for a light is painted and laser etched on the window 50. The transparent window 50 fits through the opening 46 in the thumbwheel knob 30 so that the surface on which the symbol is applied is relatively flush with the outermost surface of the knob. The light guide 32 also includes a number of angled walls 54 and a central aperture 56 for reflecting the light toward the transparent window 50 as best illustrated in
The conductor 34 is provided for completing an electrical path between the contact pads 20, 22 and moves under the influence of the thumbwheel knob 30 to create a variable signal to the light or other electrical device controlled by the thumbwheel switch assembly. The conductor 34 may be any conductive device or component, and in one embodiment, includes a number of angled metal terminals that span the two contact pads 20, 22.
The rack and pinion 36 assembly is provided for converting rotational movement of the thumbwheel knob 30 into linear motion of the conductor 34 so as to move the conductor 34 on the contact pads 20, 22 as the thumbwheel knob is rotated. An embodiment of the rack and pinion assembly comprises a rack 58 coupled with the electrical conductor 34 and a pinion 60 coupled with the light guide 32.
An embodiment of the rack 58 includes a number of spaced apart teeth mounted on a relatively planar support 59. The rack 58 may also include an opening 61 on the planar support 59 for passing light from the light source to the light guide.
An embodiment of the pinion 60 includes a number of teeth arranged in an arc or curve that mesh with the teeth on the rack 58. The pinion 60 moves with the light guide 32 and moves the rack 58 and the electrical conductor 34 when the thumbwheel knob 30 is rotated. An embodiment of the pinion 60 is integrally formed with the light guide 32.
The rack and pinion design was selected because it effectively translates rotational motion of the thumbwheel knob 30 into linear motion of the conductor 34 on the contact pads 20, 22 while simultaneously providing a constant distance from the light source 26 to the symbol 52 throughout the entire range of motion of the thumbwheel knob. This allows the light source 26 and light guide 32 to effectively and consistently illuminate the symbol on all positions of the thumbwheel knob.
The switch assembly 10 may further comprise a detent mechanism 62 for providing tactile feedback when the thumbwheel knob 30 is rotated. An embodiment of the detent mechanism 62 includes a curved track 64 with gears or teeth and a spring-biased detent pin 66 positioned in a slot of the cover plate 18. The curved track 64 is attached to one end of the keyed shaft 44 so that it rotates with the shaft when the thumbwheel knob 30 is rotated. As the thumbwheel knob 30 and detent track 64 are rotated, the detent pin 66 moves over and between the gears or teeth in the track 64 to provide tactile feedback for the thumbwheel knob.
In operation, the thumbwheel switch assembly 16 described above and other embodiments of the switch assembly may be used to dim a light or provide a variable signal to any electrical device. As the thumbwheel knob 30 is rotated, it moves the conductor 34 along the contact pads 20, 22 and adjusts a signal that passes through the conductor 34, contact pads 20, 22, and a set of resistors. For example, when the thumbwheel knob 30 is positioned at a first limit of its travel as shown in
This summary is provided to introduce a selection of concepts in a simplified form that are further described in the detailed description below. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Other aspects and advantages of the present invention will be apparent from the following detailed description of the embodiments and the accompanying drawing figures.
Although the invention has been described with reference to the preferred embodiment illustrated in the attached drawing figures, it is noted that equivalents may be employed and substitutions made herein without departing from the scope of the invention as recited in the claims. For example, many of the components shown on the circuit board 12 may be replaced and/or omitted entirely without affecting the scope of the invention.
Number | Name | Date | Kind |
---|---|---|---|
4679588 | Raab et al. | Jul 1987 | A |
6670567 | Koseki et al. | Dec 2003 | B1 |
6876313 | Hsiung et al. | Apr 2005 | B2 |
7166810 | Hanahara et al. | Jan 2007 | B2 |
7202428 | Ogawa et al. | Apr 2007 | B2 |
20110032058 | Hoess et al. | Feb 2011 | A1 |
Number | Date | Country |
---|---|---|
19840070 | Mar 2000 | DE |
102008006014 | Jul 2009 | DE |
2376284 | Dec 2002 | GB |
Entry |
---|
International Search Report and Written Opinion from PCT Application No. PCT/US2012/053454 entitled Backlit Thumbwheel Switch Assembly (Dated Feb. 20, 2013). |
Number | Date | Country | |
---|---|---|---|
20130126318 A1 | May 2013 | US |