US2485888A - Electronic tachometer and stroboscope - Google Patents
Electronic tachometer and stroboscope Download PDFInfo
- Publication number
- US2485888A US2485888A US552717A US55271744A US2485888A US 2485888 A US2485888 A US 2485888A US 552717 A US552717 A US 552717A US 55271744 A US55271744 A US 55271744A US 2485888 A US2485888 A US 2485888A
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- US
- United States
- Prior art keywords
- stroboscope
- frequency
- electronic
- electronic tachometer
- centrifuge
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000000034 method Methods 0.000 description 3
- 238000010276 construction Methods 0.000 description 2
- 239000003973 paint Substances 0.000 description 2
- 238000009987 spinning Methods 0.000 description 2
- 238000004804 winding Methods 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 238000005286 illumination Methods 0.000 description 1
- 239000003550 marker Substances 0.000 description 1
- 230000000873 masking effect Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000010349 pulsation Effects 0.000 description 1
- 230000000306 recurrent effect Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000003252 repetitive effect Effects 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P3/00—Measuring linear or angular speed; Measuring differences of linear or angular speeds
- G01P3/36—Devices characterised by the use of optical means, e.g. using infrared, visible, or ultraviolet light
- G01P3/40—Devices characterised by the use of optical means, e.g. using infrared, visible, or ultraviolet light using stroboscopic means
Definitions
- a system now in use for counting the revolutions of a centrif ugal rotor includes an electro-magnetically operated pulse generating mechanism which is adapted to cooperate with a cathode ray oscilloscope and an audio frequency oscillator, the procedure being to beat the pulses from the electro-magnetic generating apparatus with a signal from the oscillator to the end that a generally sinusoidal. pattern will be present on the screen of the oscilloscope. At this point the oscillator frequency may be checked and the speed of rotation of the centrifuge rotor determined.
- the electromagnetically operated pulse generating apparatus tends to impose a drag on the centrifuge so that maximum speeds cannot be obtained therefrom. Also, in order to insure that proper locking in of the pulse with the signal will take place, careful manual operation of the frequency control of the oscillator must be effected. In addition, the apparatus above described comprises a number of cumbersome parts and, as a result, is not easily transported.
- One of the principal objects of the present invention is to provide an improved portable, combination, self-synchronizing stroboscope and electronic tachometer which is so arranged that drag on the centrifuge rotor is eliminated,'with the result that maximum speeds may be obtained.
- Another object of the invention is to provide an apparatus of this character which, in view of the self-synchronizing feature, will be automatic in operation.
- a further object of the invention is to provide an improved process and apparatus for electronically counting recurrent action, such as the rate of revolution of a centrifuge rotor, or other rapidly moving or rotating object.
- Still another object of the invention is to provide a portable, combination, self-synchronizing be relatively simple in arrangement.
- Fig. 1 is a perspective view showing a preferred arrangement of apparatus incorporating the principles of the present invention.
- Fig. 2 is a schematic view showing the wiring diagram employed.
- the invention comprises an electronic counter which operates as a tachometer whose signal voltage is supplied by a photo-cell pick-up which sets up a pulsating current by repetitive reflection of a light beam, as from a rotating object, illustrated as a centrifugo rotor.
- a stroboscope has its trip circuit controlled and operated by the resultant frequency supplied to the electronic tachometer.
- the pick-up unit and stroboscope are individually housed in small separate casings for portability, while the electronic tachometer and other components including amplifier and power sup-- ply means may be contained in a single larger case.
- the electronic tachometer incorporates two gas discharge triodes, the pulsating output of'the pick-up unit being impresssed on their grids. The output is then fed through a suitable circuit and the frequency indicated visually on a direct current meter calibrated in cycles per second. In order to improve the accuracy of readings, three ranges are provided and these may be selected by a multiplier switch.
- the centrifuge I may be of the compressed air driven type and includes a cylindrical rotor 2 the side wall 3 of which is coated with a black masking paint throughout its periphery, except for a vertically disposed rectangular portion 4 which may be simply a cleared area, or may be formed of white paint. In either event it constitutes a bright area.
- the light source 6 and photo-electric cell I are preferably mounted in a metal case 5 of suitable design, which also contains (Fig. 2) an amplifier 8 including a vacuum tube 9 and other conventional components.
- the output of the amplifier 8 is connected by means of leads which are incorporated in a flexible cable 22, to the input of an amplifier III which is mounted in the main case, 'said case bein shown generally at H.
- the output of the amplitler I is connected to the primary winding of the couplingtransformer I 0-A, the secondary winding of said transformer being center tapped and having its end terminals connected respectively, through suitable resistors, to the grids of gas discharge tubes l2 andi3.
- the output circuit of the gas-discharge tubes is connected to the input of an electronic frequency meter which is shown at l4.
- the frequency meter which will be recognized as of a type known and commercially available, includes a double diode l and other conventional components. The range of the meter is adjustable by selection of any one of the resistors incorporated in the bank generally designated 25.
- a milliammeter l6 incorporated in the output circuit of the frequency meter is calibrated in revolutions per second.
- a stroboscope which is generally of conventional design but which is tripped by the output of amplifier 10, which is fed to strobotron 2! through an implifier 18, mounted in the main case H.
- the input of amplifier I8 is connected to the output of amplifier l0 through a coupling condenser I9.
- the operation of the stroboscope is thus automatically keyed to the rate of rotation of the centrifuge or other device under observation, which rate is represented by the pulsation frequency.
- the stroboscope therefore requires no manual adjustment, afiording perfectly timed stroboscopic illumination of the work at all times or whenever desired.
- the photo-cell pick-up unit 5 is mounted at a given distance from the orbit of portion 4 on the wall 3 of the rotor 2.
- the pulses set up by the portion 4 of the spinning rotor will control the frequency of variation of the plate current of amplifier l0 and ensues the triggeringfrequency a: the stroboscopic system as well. as: the frequencyof the output'of the gas dischargetubes; I
- the process of determining the rate of recurrence of action of a body in cyclic motion which consists in providing a substantially weightless marker by modifying the albedo of a portion of the visible surface of the body, directing radiant energy of substantially uniform intensity upon the said surface,converting some of said energy, after reflection, from said surface, into photoelectric pulses which thus occur at a frequency which is a function of the periodicity of the motion of the body, measuring and continuously indicating said frequency and thereby indicating the desired rate of recurrence of the action.
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Electromagnetism (AREA)
- Power Engineering (AREA)
- General Physics & Mathematics (AREA)
- Centrifugal Separators (AREA)
Description
Oct. 25, 1949. J. D. JORDAN 2,435,883
ELECTRONIC TACHOIE TER AND STROBOSCOPE Filed Sept. 4, 1944 I 2 Sheets-Sheet 1 FIG. I
INVENTOR JAMES 0. JORDAN ATTORNEY Oct. 25, 1949. J. D. JORDAN 2,485,838
ELECTRONIC TACHOMETER AND STROBOSC OPE I Filed Sept. 4, 1944' 2 Sheets-Sheet 2 INVENTOR' JAMES I0, JORDAN ATTORNEY Patented Oct. 25, 1949 ELECTRONIC TACHOMETER AND STROBOSCOPE James D. Jordan, Washington, D. 0., assignor to the United States of America as represented by the Secretary of the Navy Application September 4, 1944, Serial No. 552,717
1 Claim; (01. 88-14) This invention relates generally to electronic tachometers and stroboscopic viewing devices,
and more particularly to improved compact and stroboscope and electronic tachometer which will centrifuge or some other suitable spinning device. It is, of course, also desirable to learn the speed at which the apparatus is rotating and to observe the apparatus while it is in rotation, so
that comparisons can be made of the conduct of apparatus at different speeds. A system now in use for counting the revolutions of a centrif ugal rotor includes an electro-magnetically operated pulse generating mechanism which is adapted to cooperate with a cathode ray oscilloscope and an audio frequency oscillator, the procedure being to beat the pulses from the electro-magnetic generating apparatus with a signal from the oscillator to the end that a generally sinusoidal. pattern will be present on the screen of the oscilloscope. At this point the oscillator frequency may be checked and the speed of rotation of the centrifuge rotor determined.
It has been found, however, that the electromagnetically operated pulse generating apparatus tends to impose a drag on the centrifuge so that maximum speeds cannot be obtained therefrom. Also, in order to insure that proper locking in of the pulse with the signal will take place, careful manual operation of the frequency control of the oscillator must be effected. In addition, the apparatus above described comprises a number of cumbersome parts and, as a result, is not easily transported.
One of the principal objects of the present invention is to provide an improved portable, combination, self-synchronizing stroboscope and electronic tachometer which is so arranged that drag on the centrifuge rotor is eliminated,'with the result that maximum speeds may be obtained.
Another object of the invention is to provide an apparatus of this character which, in view of the self-synchronizing feature, will be automatic in operation. I
A further object of the invention is to provide an improved process and apparatus for electronically counting recurrent action, such as the rate of revolution of a centrifuge rotor, or other rapidly moving or rotating object.
Still another object of the invention is to provide a portable, combination, self-synchronizing be relatively simple in arrangement.
Other objects, not particularly mentioned hereinabove, will be evident upon consideration of this disclosure in its entirety.
In the drawings:
Fig. 1 is a perspective view showing a preferred arrangement of apparatus incorporating the principles of the present invention; and
Fig. 2 is a schematic view showing the wiring diagram employed.
Generally considered, the invention comprises an electronic counter which operates as a tachometer whose signal voltage is supplied by a photo-cell pick-up which sets up a pulsating current by repetitive reflection of a light beam, as from a rotating object, illustrated as a centrifugo rotor. A stroboscope has its trip circuit controlled and operated by the resultant frequency supplied to the electronic tachometer. The pick-up unit and stroboscope are individually housed in small separate casings for portability, while the electronic tachometer and other components including amplifier and power sup-- ply means may be contained in a single larger case. The electronic tachometer incorporates two gas discharge triodes, the pulsating output of'the pick-up unit being impresssed on their grids. The output is then fed through a suitable circuit and the frequency indicated visually on a direct current meter calibrated in cycles per second. In order to improve the accuracy of readings, three ranges are provided and these may be selected by a multiplier switch.
Referring now more particularly to the drawings, the numeral i indicates generally a centrifuge, which may be of any design or construction, and the details of which, since they form no part of the present invention, need not be considered. The centrifuge I may be of the compressed air driven type and includes a cylindrical rotor 2 the side wall 3 of which is coated with a black masking paint throughout its periphery, except for a vertically disposed rectangular portion 4 which may be simply a cleared area, or may be formed of white paint. In either event it constitutes a bright area. The light source 6 and photo-electric cell I are preferably mounted in a metal case 5 of suitable design, which also contains (Fig. 2) an amplifier 8 including a vacuum tube 9 and other conventional components.
The output of the amplifier 8 is connected by means of leads which are incorporated in a flexible cable 22, to the input of an amplifier III which is mounted in the main case, 'said case bein shown generally at H. The output of the amplitler I is connected to the primary winding of the couplingtransformer I 0-A, the secondary winding of said transformer being center tapped and having its end terminals connected respectively, through suitable resistors, to the grids of gas discharge tubes l2 andi3. The output circuit of the gas-discharge tubes is connected to the input of an electronic frequency meter which is shown at l4. The frequency meter, which will be recognized as of a type known and commercially available, includes a double diode l and other conventional components. The range of the meter is adjustable by selection of any one of the resistors incorporated in the bank generally designated 25. A milliammeter l6 incorporated in the output circuit of the frequency meter is calibrated in revolutions per second.
At I1 is shown a stroboscope which is generally of conventional design but which is tripped by the output of amplifier 10, which is fed to strobotron 2! through an implifier 18, mounted in the main case H. The input of amplifier I8 is connected to the output of amplifier l0 through a coupling condenser I9. The operation of the stroboscope is thus automatically keyed to the rate of rotation of the centrifuge or other device under observation, which rate is represented by the pulsation frequency. present in the controlling output of amplifier l0, and the stroboscope therefore requires no manual adjustment, afiording perfectly timed stroboscopic illumination of the work at all times or whenever desired.
In order to supply the necessary voltages for the amplifiers and for the stroboscope I provide a dual power supply system 20 which is mounted in the case H. The power supply 20, which will also be seen to be of conventional construction, is thought to require no detailed description.
It is believed that the operation of the invention will be evident from the foregoing. It may -be summarized briefly, however, as follows: Let
it be assumed that the centrifuge rotor is rotating at a high speed and it is desired to observe the same and to determine its speed. It will be understood that in the stroboscopic examination the purpose may be to watch the action of parts or materials in the centrifuge. The photo-cell pick-up unit 5 is mounted at a given distance from the orbit of portion 4 on the wall 3 of the rotor 2. The pulses set up by the portion 4 of the spinning rotor will control the frequency of variation of the plate current of amplifier l0 and ensues the triggeringfrequency a: the stroboscopic system as well. as: the frequencyof the output'of the gas dischargetubes; I
The combined output of tubes impressed upon the electronic frequency meter and rectified in the known mannerindicated in Fig. 2, whereby it appears as a'di'rect current tained constant, suitable voltage regulating devices are disposed in the various circuits. Suit-.- able switches are also provided to keep voltage 011 of the gas tubes I2 and i3 except when a signal v voltage is present at former I lJ-A.
By the use of my improved system, it is possible to measure speeds'of rapidly rotating objects without imposing a drag thereon.
What is claimed is:
The process of determining the rate of recurrence of action of a body in cyclic motion, which consists in providing a substantially weightless marker by modifying the albedo of a portion of the visible surface of the body, directing radiant energy of substantially uniform intensity upon the said surface,converting some of said energy, after reflection, from said surface, into photoelectric pulses which thus occur at a frequency which is a function of the periodicity of the motion of the body, measuring and continuously indicating said frequency and thereby indicating the desired rate of recurrence of the action.
JAMES D. JORDAN.
I REFERENCES CITED The following references are file of this patent:
UNITED STATES PATENTS the primary of the trans- |2 a d-lawn be of record in the
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US552717A US2485888A (en) | 1944-09-04 | 1944-09-04 | Electronic tachometer and stroboscope |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US552717A US2485888A (en) | 1944-09-04 | 1944-09-04 | Electronic tachometer and stroboscope |
Publications (1)
Publication Number | Publication Date |
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US2485888A true US2485888A (en) | 1949-10-25 |
Family
ID=24206497
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US552717A Expired - Lifetime US2485888A (en) | 1944-09-04 | 1944-09-04 | Electronic tachometer and stroboscope |
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US (1) | US2485888A (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE937978C (en) * | 1954-04-13 | 1956-01-19 | Licentia Gmbh | Speed torque measuring device |
US3194051A (en) * | 1962-09-25 | 1965-07-13 | Bendix Corp | Gyro motor bearing testing device and method |
US3274486A (en) * | 1963-03-01 | 1966-09-20 | Leon M Gould | Automatic synchronized stroboscope |
US3522432A (en) * | 1967-11-24 | 1970-08-04 | Colgate Palmolive Co | Scanning apparatus for registration marks using ultra-violet light |
US3813931A (en) * | 1973-03-15 | 1974-06-04 | Northrop Corp | Apparatus for precisely indicating position of rotational machinery |
US4653914A (en) * | 1984-03-15 | 1987-03-31 | English China Clays Lovering Pochin & Co. Limited | Monitoring deflocculated particles in a suspension |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR668568A (en) * | 1928-05-10 | 1929-11-04 | Mecanique Vibratoire | Improvement in ignition devices for stroboscopic devices |
US2043484A (en) * | 1934-06-15 | 1936-06-09 | Doherty Res Co | Variable frequency stroboscope |
US2073247A (en) * | 1934-02-05 | 1937-03-09 | Doherty Res Co | Electric flash producing method and apparatus |
US2161146A (en) * | 1936-08-15 | 1939-06-06 | Echlin Mfg Co | Apparatus for measuring frequency |
-
1944
- 1944-09-04 US US552717A patent/US2485888A/en not_active Expired - Lifetime
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR668568A (en) * | 1928-05-10 | 1929-11-04 | Mecanique Vibratoire | Improvement in ignition devices for stroboscopic devices |
US2073247A (en) * | 1934-02-05 | 1937-03-09 | Doherty Res Co | Electric flash producing method and apparatus |
US2043484A (en) * | 1934-06-15 | 1936-06-09 | Doherty Res Co | Variable frequency stroboscope |
US2161146A (en) * | 1936-08-15 | 1939-06-06 | Echlin Mfg Co | Apparatus for measuring frequency |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE937978C (en) * | 1954-04-13 | 1956-01-19 | Licentia Gmbh | Speed torque measuring device |
US3194051A (en) * | 1962-09-25 | 1965-07-13 | Bendix Corp | Gyro motor bearing testing device and method |
US3274486A (en) * | 1963-03-01 | 1966-09-20 | Leon M Gould | Automatic synchronized stroboscope |
US3522432A (en) * | 1967-11-24 | 1970-08-04 | Colgate Palmolive Co | Scanning apparatus for registration marks using ultra-violet light |
US3813931A (en) * | 1973-03-15 | 1974-06-04 | Northrop Corp | Apparatus for precisely indicating position of rotational machinery |
US4653914A (en) * | 1984-03-15 | 1987-03-31 | English China Clays Lovering Pochin & Co. Limited | Monitoring deflocculated particles in a suspension |
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