GB2125958A - Torque measurement - Google Patents
Torque measurement Download PDFInfo
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- GB2125958A GB2125958A GB08223777A GB8223777A GB2125958A GB 2125958 A GB2125958 A GB 2125958A GB 08223777 A GB08223777 A GB 08223777A GB 8223777 A GB8223777 A GB 8223777A GB 2125958 A GB2125958 A GB 2125958A
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- reflecting means
- torque
- light
- reflecting
- rotatable
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- 238000005259 measurement Methods 0.000 title description 3
- 230000003287 optical effect Effects 0.000 claims abstract description 25
- 238000000034 method Methods 0.000 claims description 15
- 230000010355 oscillation Effects 0.000 claims description 8
- 238000006073 displacement reaction Methods 0.000 claims description 2
- 238000009795 derivation Methods 0.000 claims 1
- 239000013307 optical fiber Substances 0.000 description 11
- 238000000926 separation method Methods 0.000 description 9
- 230000001419 dependent effect Effects 0.000 description 5
- 239000000463 material Substances 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000004323 axial length 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
- 239000000835 fiber Substances 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L3/00—Measuring torque, work, mechanical power, or mechanical efficiency, in general
- G01L3/02—Rotary-transmission dynamometers
- G01L3/04—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft
- G01L3/10—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating
- G01L3/12—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating involving photoelectric means
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L3/00—Measuring torque, work, mechanical power, or mechanical efficiency, in general
- G01L3/02—Rotary-transmission dynamometers
- G01L3/04—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft
- G01L3/10—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating
- G01L3/109—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating involving measuring phase difference of two signals or pulse trains
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Force Measurement Appropriate To Specific Purposes (AREA)
Abstract
In apparatus for measuring torque on a shaft (11), reflectors (12, 13) are fixed at axially spaced positions on the shaft and receive light beams from light sources (1,6) via three-port couplers (4, 9), optical fibres (3, 8) and collimators (5, 10). Pulses of light reflected back from the reflectors (12, 13) are received by light detectors (16, 17) via the optical fibres (3, 8) and the three-port couplers (4, 9). The time intervals between the respective pulses vary with the angular strain and thus the torque on the shaft (11). A microprocessor (18) computes the torque from the time intervals between the pulses and displays it on a display means (19). <IMAGE>
Description
SPECIFICATION
Apparatus and methods for measuring torque
This invention relates to apparatus and methods for measuring torque.
Conventional apparatus for measuring torque in rotating shafts of mechanical systems usually employ strain gauges. The strain gauges are bonded to the shaft of the mechanical system by means of an adhesive, so that any strains set up in the shaft cause the electrical resistance of the strain gauge to vary. A DC voltage is applied across the strain gauge, and an output DC voltage varies according to changes in the electrical resistance of the gauge. The variations in the output DC voltage, which correspond to the torque imposed in the shaft, are then monitored.
Such apparatus has the disadvantage that a battery, for providing power to the strain gauges, must be attached to the shaft, and the battery enables the gauges to be powered for limited periods only. If a long term power supply for the gauges is required, then a combination of stationary and rotating inductive couplers is needed to connect the gauges to an external power supply. A further disadvantage of such apparatus is that the DC voltage must be taken from the strain gauges by means of slip rings or a telemetry link. An embodiment of this invention, as described hereinbelow, overcomes these disadvantages.
According to the present invention there is provided apparatus for measuring torque, the apparatus comprising:
two or more reflecting means, each of said reflecting means being capable of reflecting an incident beam of parallel light back along the path of incidence of said beam of parallel light, the reflecting means being located on the periphery of a member rotatable about an axis, the two or at least two of the reflecting means being spaced axially apart on the member;
means for launching a substantially parallel beam of light from one end of a first optical path such that the light is incident normally on one of said two reflecting means at a first instant of time during each revolution of the member;;
means for launching a substantially parallel beam of light from one end of a second optical path such that the light is incident normally on the other of said two reflecting means at a second instant of time during each revolution of the member;
means for receiving each of the parallel beams of light after the parallel beams have been reflected from said two reflecting means; and
means for measuring the time interval between said received light beams.
The time intervals between three successively received light beams gives rise to two different time intervals, the sum of which equals the time taken for the rotatable member to complete one revolution. Each of the time intervals is proportional both to the speed of the rotatable member and to the angular strain imparted to the shaft and therefore to the torque. So, in a given rotatable member and arrangement of apparatus, the value of a ratio of either of the two different time intervals to the sum of the two different time intervals corresponds to the torque exerted along the rotatable member. The ratio is independent of the speed of rotation of the rotatable member, and hence, by comparing the magnitude of the ratio to values previously obtained for known torques, the torque may be determined.Absolute values of the torque may, for example, be determined from a known relation:
JGA0
T=
L where
T=Torque
J=Torsional second moment of area (torsional
constant)
G=Shear modulus AO=Change in angular separation of two
reflecting means caused by the torque T.
L=Distance between the two reflecting means.
The torsional constant J is dependent on the physical parameters of the shaft, and the shear modulus G is dependent on the material of the shaft. Hence, by substituting the abovementioned parameters and the change in angular separation AO of the two reflecting means into the above relation, the torque causing the change can be determined.
According to the present invention there is also provided a method for measuring torque, the method comprising the steps of:
locating two or more reflecting means, each of said reflecting means being capable of reflecting an incident beam of parallel light back along the path of incidence of said beam of parallel light, on the periphery of a member rotatable about an axis, spacing the two or at least two of the reflecting means axially apart;
launching a substantially parallel beam of light from one end of a first optical path such that the light is incident normally on one of said two reflecting means at a first instant of time during each revolution of the member;;
launching a substantially parallel beam of light from one end of a second optical path such that the light is incident normally on the other of said two reflecting means at a second instant of time during each revolution of the member;
receiving light reflected from each of said reflecting means into respective ends of the first and second optical paths during each revolution of the member; and
measuring the time interval between the received light beams.
The reflecting means are preferably in the form of planar mirrors or prisms mounted onto the periphery of, for example, a rotary member in the form of a drive shaft of a mechanical system. The parallel light beams are preferably received by the ends of the first and second optical paths from which they were launched, thus reducing the bulk of apparatus required. Since no coupling system is necessary between the shaft of the mechanical system and the parallel beam launching means, it is possible to make continuous measurements over an indefinite period of time because the plantar mirrors mounted on the shaft do not need a power supply and remaining parts of the apparatus can be powered from the mains.
Furthermore, apparatus embodying this invention may be set up quickly and cheaply. A notable advantage of this is that once the planar reflective surfaces have been mounted onto the shaft, they may be left there permanently. The remaining parts of the apparatus, therefore, may be set up and dismantled without the need to stop the mechanical system operating.
The invention will now be further described by way of illustrative and non-limiting example, with reference to the accompanying drawing, in which:
Figure 1 is a diagrammatic view showing a drive shaft of a mechanical system and a torque measuring apparatus embodying this invention; and
Figure 2 is an end view of the drive shaft of
Figure 1.
Figure 1 shows a light source 1 which may comprise, for example, a laser or a light emitting diode. The light source 1, which is connected to an optical fibre 2, generates light in pulse or continuous form and launches the light into the optical fibre 2. The optical fibre 2 is coupled to a first optical fibre 3 by means of, for example, a three-port coupler 4. The end of the first optical fibre 3 not coupled with the optical fibre 2 is coupled to a light collimating means 5. Figure 1 also shows a light source 6 connected to an pptical fibre 7, which optical fibre 7 is coupled to a second optical fibre 8 by means of a three-port coupler 9 in the same way to that of the optical fibre 2. The end of the second optical fibre 8 not coupled with the optical fibre 7 is coupled to a light collimating means 10.The light collimating means 5 and 10 are arranged so that their centres lie in a line parallel to the axis of a drive shaft 11, and are capable of emitting parallel beams of light and receiving beams of light which have been reflected from two reflecting means, for example, planar mirrors 12 and 13. The planar mirrors 12 and 1 3 are located on the peripheral surface of the drive shaft 11 and are spaced axially apart.
The illustrated apparatus is operative to measure any static and/or dynamic torque applied to the drive shaft 11 by determining the torsional strain between the respective locations of the planar mirrors 12 and 13 by measuring the charge in angular spacing (as will be described below) from that when no torque is applied to the drive shaft 11.
Figure 2 is an end view of the drive shaft 11 taken in the direction of an arrow A (Figure 1), and also shows the light collimating means 10 (the light collimating means 5 lying behind the collimating means 10). As can be seen from
Figure 2, the planar mirrors 12 and 13 are angularly separated by an angle O in a circumferential direction of the shaft 11. The light collimating means 5 and 10 are disposed relative to the planar mirrors 12 and 13 in such a way that the parallel beam of light emitted from the light collimating means 5 is incident normally on the planar mirror 12 at a first instant in time during a revolution of the shaft 11 and the parallel beam of light from the light collimating means 10 is incident normally on the planar mirror 13 at a second and different instant in time during a revolution of the shaft 11.The second instant is subsequent to the first if, for example, the shaft
11 is rotating about its axis in a direction shown by an arrow B. Consequently, at the first and second instants in time, beams of light are reflected by the respective planar mirrors 12 and 1 3 back along their incident paths. The reflected beams of light are then received by the collimating means 5 and 10 respectively, thus defining an interval of time between the first instant and the second instant of time. After being received by the collimating means 5 and 10, the beams of light are transmitted back down the optical fibres 3 and 8. Since the planar mirrors 12 and 13 are perpendicular to the collimated beams of light for substantially only an instant in time, the beams of light transmitted back down the optical fibres 3 and 8 will be in pulse form.The pulses are passed into optical fibres 14 and 1 5 by means of the three-port couplers 4 and 9 respectively, where they are then transmitted to light detectors 1 6 and 17, having response times fast enough to resolve successive pulses received from the optical fibres 14 and 1 5. The light detectors 1 6 and 1 7 detect the light pulses and generates electrical pulses in response thereto.
The time interval between successive beams of light being received by the collimating means 5 and 10 respectively are identical, but dependent upon the rotation speed R of the shaft 11.
However, due to the angular separation 6 between the planar mirrors 1 2 and 13, the beams of light received by the collimating means 5 will occur at different instants in time to those received by the collimating means 1 0. However, the beams of light will be received alternately by the respective collimating means 5 and 10, therefore giving rise to two time intervals per revolution. When the shaft 11 is not under the influence of any torque along its axial length, the time interval between the first instant of time when beams of light are received by the collimating means 5 and the second instant of time when beams of light are received by the collimating means 10 is designated t, and the time interval between the second instant of time when beams of light are received by the collimating means 10 and the next instant of time when beams of light are received by the collimating means 5 is designated t2 (see Figure 2). The times t1 and2, therefore, remain constant and are known for a particular shaft having planar mirrors 12 and 1 3 located at given locations.
When a torque is imposed on the shaft 11 between the two planar mirrors 12 and 13, the angle 0 is caused to vary. For a given torque the angle 0 will remain constant, but different from the angle when no torque is being imposed. As a result of changes in the angular separation 0 between the planar mirrors 12 and 13, the time intervals t, and t2 vary and for a particular torque change to t3 and t4 respectively. The values oft3 and t4 are indicative of the torque in the shaft 11 when compared with previously obtained values, but when values of the torque are to be determined without reference to previously obtained values, it is the change in the time intervals from t, and t2 to t3 and t4 that is indicative of the torque.The sum of the two time intervals t1 and t2 remains constant provided the shaft 10 continues to rotate at the same speed R, but if the sum t,+t2 varies, then the speed of the shaft in revolutions per second may be determined from the reciprocal of t,+t2 (i.e. the
sum t,+t2 is inversely proportional to the rotation speed of the shaft 11).
A method by which the torque values may be obtained from measurements of the values of t,, t2, and t3, t4 is described below. The electrical pulses generated by the light detectors 16 and 17 correspond to light pulses received by the collimating means 5 and 10, and hence the time intervals between the electrical pulses correspond to t,, t2 when no torque is applied, and t3, t4 when a torque is applied to the shaft 1 The electrical pulses are passed to a microprocessor 1 8 which measures the time intervals between them, thus producing the values t1, t2, t3 and t4.The microprocessor 1 8 computes a relation:: {t3/(t3 +t4)t,/(t, +t2) I or { t4/(t3 +t4)t2/(t, +t2)1 which, for a particular shaft, represents the magnitude of a torque in the shaft 11. The value of each of the four ratios mentioned in the above relation is independent of the speed of rotation of the shaft 11. The value of the ratio t1/(t1+t2) or t2/(t1+t2) is constant for a given machine since it is the ratio for zero torque.By subtracting t,/(t, +t2) or t2/(t1+t2) from the ratio
t3/(t3+t4) or t4/(t3+t4) respectively (which ratios correspond to the angular separation of the planar mirrors 12 and 1 3 when the shaft has a torque imposed on it), a parameter A0 representing the change in the angular separation when the shaft 11 is under a torque from the separation when no torque is applied, is obtained. This parameter may be compared with previously obtained parameters for known torques or an absolute value for the torque may be computed.An absolute value for the newly applied torque may be computed from the relation: JGAS T=
L where
T=Torque
J=Torsional second moment of area (torsional
constant)
G=Shear modulus A0=Change in angular separation of the planar
mirrors 12 and 13 caused by the torque T.
L=Distance between the planar mirrors 12 and
13.
The torsional constant J is dependent on the physical parameters of the shaft, and the shear modulus G is dependent on the material of the shaft. Hence, by substituting the abovementioned parameters and the change in angular separation A0 of the planar mirrors 12 and 1 3 into the above relation, the torque causing the change can be determined. The computation may be carried out by means of the microprocessor 18, the microprocessor 1 8 storing the previously obtained ratios or the values for the abovementioned relation. Then the value of the newly applied torque is transmitted to a meter or display means 19.
The direction of the torque also may be determined. For example, if a torque is exerted in the direction of arrow B in Figure 2, the ratio t3/(t3+t4) will be less than the ratio t,/(t,+t2). If the torque is exerted in the opposite direction to the arrow B, the ratio t3/(t3+t4) will be greater than the ratio t,/(t,+t2). Hence, by observing the relative change between these ratios, the direction as well as magnitude of the torque may be determined.
Embodiments of this invention are not limited to torque measuring apparatus comprising only two reflecting means. A number of reflecting means greater than two may be employed and a corresponding number of light collimating means may be used for measuring the torque between two or more points on the shaft 11. A plurality of reflecting means may be located on the periphery of the shaft 11 at the same axial location, which enables dynamic torque (that it, a measure of torsional oscillation in the shaft 11 as it rotates) to be measured.The number of reflecting means at an axial location must be equal to two or more times the frequency of the oscillation to be measured (since, for a sine wave of frequency f to be reconstructed, the wave must be sampled at twice its frequency f), so if the frequency of the oscillation is once per revolution of the shaft, then two reflecting means should be located at an axial location, which gives rise to two light pulses per revolution. The microprocessor 1 8 may be programmed to compute the dynamic torque from the time intervals between the two pulses and the time intervals between the two pulses received when no torque is exerted along the length of the shift 11. If the frequency of oscillation is N times the shaft speed, where N is an integer, then 2N reflecting means are needed at an axial location.
When, for example, eight reflecting means are employed at the same axial location, it is preferable to arrange one of the eight reflecting means to reflect a different colour light beam to that of the other seven reflecting means so that the microprocessor 18 may be provided with a reference signal, once per revolution of the shaft 11.
It should be noted that although the collimating means 5 and 1 Q of the embodiment described above are arranged so that their centres lie in a line parallel to the axis of the shaft 11, and the reflecting means 12 and 13 are angularly separated by an angle 0, the collimating means 5 and 10 may alternatively be angularly separated and/or the reflecting means 12 and 13 may or may not be angularly separated, provided that there is relative angular displacement between the reflected light beams.
Claims (Filed on 3/8/83)
1. Apparatus for measuring torque on a member rotatable about an axis, the apparatus comprising:
two or more reflecting means each capable of reflecting an incident substantially parallel beam of light back along the path of incidence of the beam, the reflecting means being located on the periphery of the rotatable member and the two or at least two of the reflecting means being spaced axially apart on the member;
means for launching a substantially parallel beam of light from one end of a first optical path such that the light is incident normally on one of said two reflecting means at a first instant of time during each revolution of the member;;
means for launching a substantially parallel
beam of light from one end of a second optical
path such that the light is incident normally on the
other of said two reflecting means at a second
instant of time during each revolution of the
member;
means for receiving each of the beams of light
after they have been reflected from said two
reflecting means; and
means for measuring the time intervals
between said received light beams.
2. Apparatus according to claim 1, so arranged
that the light beams reflected from the reflecting
means are received by the ends of the optical
paths from which they were launched.
3. Apparatus according to claim 1 or claim 2,
including:
means for computing the ratio t/t', where t
equals the time interval between received light
beams reflected from respective ones of said two
reflecting means and t' equals the time interval
between successive received light beams
reflected from one of said two reflecting means,
whereby the ratio t/t' represents the angular
relationship of said two reflecting means with
respect to the axis of the rotatable member and therefore varies with the angular strain (and thus the torque) on the rotatable member, independently of its speed of rotation; and
means for comparing the computed ratio t/tt with a value representing the same ratio for a predetermined torque on the rotatable member, thereby to derive a signal representative of the current torque on the member.
4. Apparatus according to claim 3, wherein the comparing means is operative to subtract said computed ratio and said value representing the same ratio for a predetermined torque on the rotatable member, whereby said signal representative of the current torque on the member represents the change (AO) in the angular relationship of said two reflecting means due to the difference between the current and predetermined torques.
5. Apparatus according to claim 4, wherein the comparing means is operative to derive the sign of the result of said subtraction and thus to indicate the sense of the current torque.
6. Apparatus according to claim 4 or claim 5, including means to compute the value of the current torque (T) from the signal AS in accordance with the relationship: JGAO T=
L where:
J=the torsional second moment of area
(torsional constant) of the member;
G=the shear modulus of the member; and
L=the distance between said two reflecting
means.
7. Apparatus according to any one of the preceding claims, including a plurality of the reflecting means spaced around the member at the same axial position with respect thereto such that each successively reflects said beam of light incident thereon from the same one of the optical paths, and means responsive to the time intervals between such successive reflections to determine dynamic torque on the rotary member, that is torsional oscillation of the member as it rotates.
8. Apparatus for measuring torque on a member rotatable about an axis, the apparatus being substantially as herein described with reference to the accompanying drawing.
9. A method of measuring torque on a member rotatable about an axis, the method comprising the steps of:
locating two or more reflecting means, each capable of reflecting an incident substantially parallel beam of light back along the path of incidence of the beam, on the periphery of the rotatable member such that the two or at least two of the reflecting means are spaced axially apart on the member;
launching a substantially parallel beam of light from one end of a first optical path such that the light is incident normally on one of said two reflecting means at a first instant of time during each revolution of the member;
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (16)
1. Apparatus for measuring torque on a member rotatable about an axis, the apparatus comprising:
two or more reflecting means each capable of reflecting an incident substantially parallel beam of light back along the path of incidence of the beam, the reflecting means being located on the periphery of the rotatable member and the two or at least two of the reflecting means being spaced axially apart on the member;
means for launching a substantially parallel beam of light from one end of a first optical path such that the light is incident normally on one of said two reflecting means at a first instant of time during each revolution of the member;;
means for launching a substantially parallel
beam of light from one end of a second optical
path such that the light is incident normally on the
other of said two reflecting means at a second
instant of time during each revolution of the
member;
means for receiving each of the beams of light
after they have been reflected from said two
reflecting means; and
means for measuring the time intervals
between said received light beams.
2. Apparatus according to claim 1, so arranged
that the light beams reflected from the reflecting
means are received by the ends of the optical
paths from which they were launched.
3. Apparatus according to claim 1 or claim 2,
including:
means for computing the ratio t/t', where t
equals the time interval between received light
beams reflected from respective ones of said two
reflecting means and t' equals the time interval
between successive received light beams
reflected from one of said two reflecting means,
whereby the ratio t/t' represents the angular
relationship of said two reflecting means with
respect to the axis of the rotatable member and therefore varies with the angular strain (and thus the torque) on the rotatable member, independently of its speed of rotation; and
means for comparing the computed ratio t/tt with a value representing the same ratio for a predetermined torque on the rotatable member, thereby to derive a signal representative of the current torque on the member.
4. Apparatus according to claim 3, wherein the comparing means is operative to subtract said computed ratio and said value representing the same ratio for a predetermined torque on the rotatable member, whereby said signal representative of the current torque on the member represents the change (AO) in the angular relationship of said two reflecting means due to the difference between the current and predetermined torques.
5. Apparatus according to claim 4, wherein the comparing means is operative to derive the sign of the result of said subtraction and thus to indicate the sense of the current torque.
6. Apparatus according to claim 4 or claim 5, including means to compute the value of the current torque (T) from the signal AS in accordance with the relationship: JGAO T=
L where:
J=the torsional second moment of area
(torsional constant) of the member;
G=the shear modulus of the member; and
L=the distance between said two reflecting
means.
7. Apparatus according to any one of the preceding claims, including a plurality of the reflecting means spaced around the member at the same axial position with respect thereto such that each successively reflects said beam of light incident thereon from the same one of the optical paths, and means responsive to the time intervals between such successive reflections to determine dynamic torque on the rotary member, that is torsional oscillation of the member as it rotates.
8. Apparatus for measuring torque on a member rotatable about an axis, the apparatus being substantially as herein described with reference to the accompanying drawing.
9. A method of measuring torque on a member rotatable about an axis, the method comprising the steps of:
locating two or more reflecting means, each capable of reflecting an incident substantially parallel beam of light back along the path of incidence of the beam, on the periphery of the rotatable member such that the two or at least two of the reflecting means are spaced axially apart on the member;
launching a substantially parallel beam of light from one end of a first optical path such that the light is incident normally on one of said two reflecting means at a first instant of time during each revolution of the member;
launching a substantially parallel beam of light from one end of a second optical path such that the light is incident normally on the other of said two reflecting means at a second instant of time during each revolution of the member;
receiving each of the beams of light after they have been reflected from said two reflecting means; and
measuring the time intervals between the received light beams.
10. Apparatus according to claim 9, wherein the light beams reflected from the reflecting means are received by the ends of the optical paths from which they were launched.
11. Apparatus according to claim 9 or claim 10, including the steps of:
computing the ratio t/t', where t equals the time interval between received light beams reflected from respective one of said two reflecting means and t' equals the time interval between successive received light beams reflected from one of said two reflecting means, whereby the ratio t/t' represents the angular relationship of said two reflecting means with respect to the axis of the rotatable member and therefore varies with the angular strain (and thus the torque) on the rotatable member, independently of its speed of rotation; and
comparing the computed ratio t/t' with a value representing the same ratio for a predetermined torque on the rotatable member, thereby to derive a signal representative of the current torque on the member.
12. A method according to claim 1 wherein said comparison comprises subtraction of said computed ratio and said value representing the same ratio for a predetermined torque on the rotatable member, whereby said signal representative of the current torque on the member represents the change (AS) in the angular relationship of said two reflecting means due to the difference between the current and predetermined torques.
1 3. A method according to claim 12, wherein said comparison operation includes derivation of the sign of the result of said subtraction to thereby indicate the sense of the current torque.
14. A method according to claim 12 or claim 13, including the step of computing the value of the current torque (T) from the signal AO in according with the relationship: JGhO L where:
J=the torsional second moment of area
(torsional constant) of the member;
G=the shear modulus of the member; and
L=the distance between the said two reflecting
means.
1 5. A method according to any one of claims 9 to 14, including attaching a plurality of the reflecting means at positions spaced around the member at the same axial position with respect thereto such that each successively reflects a said beam of light incident thereon from the same one of the optical paths, and determining, from the time intervals between such successive reflections, dynamic torque on the rotary member, that is torsional oscillation of the member as it rotates.
16. A method of measuring torque on a member rotatable about an axis, the method being substantially as herein described with reference to the accompanying drawing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08223777A GB2125958B (en) | 1982-08-18 | 1982-08-18 | Torque measurement |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08223777A GB2125958B (en) | 1982-08-18 | 1982-08-18 | Torque measurement |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2125958A true GB2125958A (en) | 1984-03-14 |
| GB2125958B GB2125958B (en) | 1986-01-22 |
Family
ID=10532379
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08223777A Expired GB2125958B (en) | 1982-08-18 | 1982-08-18 | Torque measurement |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2125958B (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5001937A (en) * | 1989-11-06 | 1991-03-26 | Tacan Corporation | Optically based torsion sensor |
| FR2664696A1 (en) * | 1990-07-13 | 1992-01-17 | Gen Electric | Method and device for measuring the torque of a shaft |
| EP0609726A3 (en) * | 1993-02-01 | 1994-10-26 | Liberty Tech Center | A system for determining shaft load parameters including shaft windup angle per unit length, torque output and power output in a generally cylindrical rotating shaft. |
| DE4425503C1 (en) * | 1994-07-20 | 1995-07-06 | Guenter Prof Dr Ing Ebi | Simultaneous measurement of torsional and axial stresses on rotating shaft or comparable workpiece |
| WO1999022211A1 (en) * | 1997-10-23 | 1999-05-06 | Siemens Aktiengesellschaft | Torque measurement using concentrating reflectors on the rotating shaft |
| EP1398608A3 (en) * | 2002-09-06 | 2005-02-09 | General Electric Company | High resolution torque measurement on a rotating shaft |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB946140A (en) * | 1961-05-04 | 1964-01-08 | Ford Motor Co | Improvements in or relating to torquemeters |
| GB1008494A (en) * | 1963-08-20 | 1965-10-27 | Ford Motor Co | Improvements in or relating to apparatus for use in measuring torques |
| GB1091577A (en) * | 1965-07-14 | 1967-11-22 | Blackstone & Co Ltd | Improvements in or relating to torque responsive devices |
| GB2049169A (en) * | 1979-03-27 | 1980-12-17 | Univ Kingston | Torque transducer |
-
1982
- 1982-08-18 GB GB08223777A patent/GB2125958B/en not_active Expired
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB946140A (en) * | 1961-05-04 | 1964-01-08 | Ford Motor Co | Improvements in or relating to torquemeters |
| GB1008494A (en) * | 1963-08-20 | 1965-10-27 | Ford Motor Co | Improvements in or relating to apparatus for use in measuring torques |
| GB1091577A (en) * | 1965-07-14 | 1967-11-22 | Blackstone & Co Ltd | Improvements in or relating to torque responsive devices |
| GB2049169A (en) * | 1979-03-27 | 1980-12-17 | Univ Kingston | Torque transducer |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5001937A (en) * | 1989-11-06 | 1991-03-26 | Tacan Corporation | Optically based torsion sensor |
| FR2664696A1 (en) * | 1990-07-13 | 1992-01-17 | Gen Electric | Method and device for measuring the torque of a shaft |
| EP0609726A3 (en) * | 1993-02-01 | 1994-10-26 | Liberty Tech Center | A system for determining shaft load parameters including shaft windup angle per unit length, torque output and power output in a generally cylindrical rotating shaft. |
| DE4425503C1 (en) * | 1994-07-20 | 1995-07-06 | Guenter Prof Dr Ing Ebi | Simultaneous measurement of torsional and axial stresses on rotating shaft or comparable workpiece |
| US5747699A (en) * | 1994-07-20 | 1998-05-05 | Ebi; Guenter | Method of measuring torsional stresses and/or axial stresses on a rotating shaft or on a comparable workpiece |
| WO1999022211A1 (en) * | 1997-10-23 | 1999-05-06 | Siemens Aktiengesellschaft | Torque measurement using concentrating reflectors on the rotating shaft |
| US6318187B1 (en) | 1997-10-23 | 2001-11-20 | Siemens Aktiengesellschaft | Apparatus for torque measurement on rotating torque shafts |
| EP1398608A3 (en) * | 2002-09-06 | 2005-02-09 | General Electric Company | High resolution torque measurement on a rotating shaft |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2125958B (en) | 1986-01-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |