The following operators can be used to better focus your queries.
( ) , AND, OR, NOT, W/#
? single char wildcard, not at start
* multi char wildcard, not at start
(Cat? OR feline) AND NOT dog?
Cat? W/5 behavior
(Cat? OR feline) AND traits
Cat AND charact*
This guide provides a more detailed description of the syntax that is supported along with examples.
This search box also supports the look-up of an IP.com Digital Signature (also referred to as Fingerprint); enter the 72-, 48-, or 32-character code to retrieve details of the associated file or submission.
Concept Search - What can I type?
For a concept search, you can enter phrases, sentences, or full paragraphs in English. For example, copy and paste the abstract of a patent application or paragraphs from an article.
Concept search eliminates the need for complex Boolean syntax to inform retrieval. Our Semantic Gist engine uses advanced cognitive semantic analysis to extract the meaning of data. This reduces the chances of missing valuable information, that may result from traditional keyword searching.
An optical tachometer is constructed with a sealing ring to prevent the entry of contaminants into the "window" area of the device.
English (United States)
This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
100% of the total text.
Page 1 of 2
Prevention of Contamination in an Optical Tachometer
An optical tachometer is constructed with a sealing ring to prevent the entry
of contaminants into the "window" area of the device.
A tachometer consists of a rotating disk 10 and a stationary mask 11 which
causes lines engraved photographically upon the inside surface 12 of the disk 10
to rotate past a light emitting diode (LED) 13 and a phototransistor 14, thus
allowing the sensing of the speed of the rotating shaft 15 to which the rotating
disk is attached by means of a set screw 16.
Since it is necessary to maintain a fixed distance between the rotating disk 10
and the stationary mask 11, the device described here provides the required
separation by means of a plastic ring 17 bonded firmly to the rotating disk 10.
The exposed surface 18 of the ring rides on mask 11; the ring is of the correct
thickness to provide the required gap 20.
The ring 17 is mounted near the outside diameter of the disk 10. This
configuration acts as a rotating seal. The surfaces 12 and 19 on disk 10 and
mask 11 are thus protected against contamination, which would otherwise act to
degrade the amount of light passing through the disk and mask from the LED to
the phototransistor. This is especially valuable in a contaminated environment.
Page 2 of 2
[This page contains 3 pictures or other non-text objects]