Claims
- 1. A lens comprising:
a first face;
the first face comprising a concentric channel around a circumferential edge of the lens; and a second face;
the second face comprising a concentric projection around the circumferential edge of the lens; wherein when at least two lenses are stacked upon each other, the concentric projection of the second face of a first lens engages the concentric channel of the first face of a second lens,
preventing relative movement between the first lens and the second lens; and maintaining a gap between the second face of the first lens and the first face of the second lens.
- 2. A lens as described in claim 1, wherein
at least a portion of the first face comprises an optical surface; and the concentric channel further comprises:
a first wall; and a second wall; wherein
the first wall and the second wall form the bounds of the concentric channel; and at least one of the first wall and the second wall projects above the optical surface; wherein the optical surface of the first face is protected from scratches and other damage when the lens is set upon a generally flat surface.
- 3. A lens as described in claim 1, wherein
at least a portion of the second face comprises an optical surface; and the concentric projection projects above the optical surface; wherein the optical surface of the second face is protected from scratches and other damage when the lens is set upon a generally flat surface.
- 4. A knob assembly comprising:
a knob;
the knob containing a generally cylindrical cavity formed by a contiguous interior wall of the knob; the interior wall further comprising at least one key protruding into the cavity; and a shaft with a generally cylindrical first end, the first end of the shaft further comprising:
at least one concentric barb formed around the first end of the shaft, wherein
the circumference of the barb is slightly larger than the circumference of the cavity; and at least one keyway formed to accept the key in the knob cavity,
the keyway interrupting the contiguity of the at least one concentric barb; wherein when the key in the cavity and keyway on the shaft are aligned, the knob may be pushed upon the first end of the shaft, the first end of the shaft thereby filling the cavity, and the interface of the at least one barb with the interior wall of the knob inhibiting the knob from being pulled off the shaft, and the interface of the at least one key and the at least one keyway preventing the knob from rotating relative to the shaft.
- 5. A knob assembly as described in claim 4, wherein the knob is constructed of a minimally compressive, elastomeric material.
- 6. A knob assembly as described in claim 5, wherein the elastomeric material comprises rubber.
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. application Ser. No. 09/912,196 entitled “Slim Profile Indicating Instruments”, filed 23 Jul. 2001, which claimed the benefit of U.S. provisional application No. 60/220,456 entitled “Slim Profile Tachometer,” filed on 24 Jul. 2000. Each of the above-referenced applications is hereby incorporated by reference as though fully set forth herein.
Provisional Applications (1)
|
Number |
Date |
Country |
|
60220456 |
Jul 2000 |
US |
Divisions (1)
|
Number |
Date |
Country |
Parent |
09912196 |
Jul 2001 |
US |
Child |
10686819 |
Oct 2003 |
US |