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Digital Optical Tachometer

IP.com Disclosure Number: IPCOM000081583D
Original Publication Date: 1974-Jul-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Richards, LD: AUTHOR [+2]

Abstract

This digital optical tachometer is of the see-thru type and includes a housing which encloses the entire optical assembly, while at the same time providing mounting arrangements for the tachometer's stationary mask, photocell, light source and associated electronic circuitry.

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Digital Optical Tachometer

This digital optical tachometer is of the see-thru type and includes a housing which encloses the entire optical assembly, while at the same time providing mounting arrangements for the tachometer's stationary mask, photocell, light source and associated electronic circuitry.

Fig. 1 shows a motor 10 having a rotary output shaft 11 for driving a load, not shown. A slotted drum 12 is connected to the opposite end of the shaft, to rotate therewith. This drum includes a large number of equally spaced open slots about its circumference. These slots are aligned parallel to the motor's rotational axis.

Housing 13 totally encloses drum 12, and mounts to the motor's end bells by three fasteners 14.

In Fig. 2, the housing is assembled on the end bell and the tachometer is shown in section.

The end wall of the housing 13 includes boss 15 which extends into the central portion of drum 12. This boss mounts light-emitting diode 16 and directs its light beam through the drum slots to the adjacent wall of the housing. This wall of the housing 13 mounts the tachometer's stationary mask 17. In the alternative, mask 17 may be formed as an integral part of housing 13. This mask includes an open slot pattern of similar spacing to that of the drum 12. The housing wall behind the mask includes opening 18. This opening receives photocell 19, in alignment with the diode's light path.

The photocell 19 is mounted on circuit card 20. This card is, in turn, mounted...