Decree No. 66 / 2004 Coll.
Order setting out the requirements for torque control keys
Valid
Effective from 01.03.2004
66
DECLARATION
of 3 February 2004
laying down requirements for torque control keys
The Ministry of Industry and Trade provides pursuant to Section 27 of Act No. 505 / 1990 Coll., on Metrology, as amended by Act No. 119 / 2000 Coll. and Act No. 137 / 2002 Coll., ("the Act") for the implementation of Sections 6 (2) and 9 (1) of the Act:
This Decree sets out the requirements for torque control keys ("torque keys'), which are divided into types I and II, as well as the procedure for their approval and verification.
(1) For the purposes of this Decree, the torque keys of type I (Annex Figure 1) shall be:
(a) Class A: torque keys with twisted or bent bars,
(b) Class B: torque wrenches with fixed body, with a scale or digit deviation or display,
(c) Class C: torque wrenches with fixed wrenches and electronic measuring system,
(d) Class D: torque screwdrivers with a scale or with a number indicator or display; and
(e) class E: torque screwdrivers with electronic measuring system.
(2) For the purposes of this Decree, the torque keys of type II (Annex, Figure 2) shall be:
(a) Class A: torque wrench adjustable by scale,
b) Class B: torque key fixed,
(c) Class C: torque wrench adjustable without scale,
d) Class D: torque screwdriver adjustable by scale,
e) Class E: torque screwdriver fixed and
f) Class F: torque screwdriver adjustable without scale.
The terminology and the requirements for torque keys, the type-approval procedure and the verification procedure are set out in the Annex.
This Decree shall take effect on 1 March 2004.
Minister:
Ing. Urban v. r.
Annex to Decree No 66 / 2004 Coll.
1. TERMINOLOGY
1.1. The torque control key is the torque key used to check the tightening of bolt connections on steel structures, motor vehicle wheels and in other cases where life or property may be endangered in case of release of bolt connections.
1.2. Moment keys of type I (pointing torque keys) are torque keys with a mechanical or electronic measuring system with a scale which show directly the value of the measured moment of force in units of force or in values of proportional moment of force (sections).
1.3. Type II torque keys (limit torque keys) are torque keys that indicate the achievement of the set torque by mechanical, acoustic or optical means. This moment can be set by scale for these keys, without scale to a certain value, or it can be set firmly.
1.4. The measurement range is the range of moments of force that can be measured by the torque key.
1.5. The lower limit of the measurement range is the smallest value of the torque force that can be measured with the torque key. The value of the lower measurement range limit for torque wrenches with a scale should be less than or equal to 20% of the upper measurement range limit.
1.6. The upper limit of the measurement range is the largest or nominal torque value of the torque key.
1.7. The torque key scale is for torque keys type Even a device indicating the value of the measured moment of force. For type II torque keys, the force torque to be achieved is set according to the scale.
1.8. The estimated deviation of indication E indicates the interval between the actual deviations of the moment of force from the indicated value. It is given in units of moment of force mN.m, N.m or kN.m
1.9. The actual moment X is the moment that is set on the verification device. It is given in units of moment of force mN.m, N.m or kN.m
1.10. The verification point is the point of the torque of the force at which the torque key is verified.
1.11. The mean value of the verification device data is the arithmetic mean of the values measured on the scale of the verified instrument, determined from five series of measurements (n-series of measurements) at a specific verification point. Marked as M ^ a is given in units of moment of force N.m.
1.12. The nominal torque is the indication of the verification device when reaching the nominal torque of the torque key. Marked M and given in units of moment of force N.m
1.13. The value of the actual moment at the verification point is the scale of the verified instrument at the jth load at the verification point. Marked Mj and given in units of moment of force N.m
1.14. Indicated value on the torque key. It is a value that is set on the torque key or shown on the torque key scale at the jth verification point. Marked Xj is given in units of force N.m or parts.
1.15. Nominal value indicated on the torque key. It's usually the upper limit of the measuring range. It is marked XE and is given in units of moment force N.m or parts.
1.16. Indicated value calculated from the theoretical curve of linear regression. It is marked Xa and is given in units of moment force N.m or parts.
1.17. The sensitivity coefficient indicates the ratio between the data on the scale and the etalon moment. Marked S.
1.18. The repeatability of the torque key shall be calculated as the sampling standard deviation from the five measured force torque values at the jth verification point. It is marked b 'a is given in units of the moment of force N.m.
1.19. The deviation of the indication shall be determined as the difference between the values shown (or set) on the torque key scale for the jth verification step and the actual moment of force given by the etalon instrument. Marked with fq and given in units of moment of force N.m
1.20. The coefficient of extension is a coefficient indicating for probability p = 0,95 the magnitude of the confidence interval. Marked for a is dimensionless.
1.21. The relative deviation of the torque key indication is the deviation of the indication relative to the measured value. Indicates q and is given in%.
1.22. Differentiability is the smallest change of data that can be read or set on the torque key scale. Marked r and given in units of moment of force N.m
1.23. The expanded uncertainty of the torque key verification indicates the measurement reliability interval for p = 0,95. Marked U and given in units of moment force N.m
1.24. The best measuring ability of the laboratory is the best value of the expanded uncertainty the laboratory can achieve. It is called Ubmc and is given in units of moment force N.m.
1.25. The standard repeatability uncertainty is a partial verification uncertainty involving the repeatability of the torque key verification. It is marked ub 'and is given in units of moment force N.m.
1.26. Standard uncertainty of the best measurement capability of an etalon instrument is used to calculate the expanded uncertainty of the verified torque key and is obtained as a proportion of the value of the best measurement capability and the coefficient of expansion. It is marked ubmc a. is given in units of moment force N.m.
1.27. The standard uncertainty of the mean value indicates a deviation of the measured values from the mean value. Marked for (M) and given in units of moment force N.m
1.28. The standard uncertainty of the resolution of the torque key characterises the uncertainty caused by the limited resolution of the torque key. Indicates ur and in units of moment of force N.m.
1.29. The expanded relative uncertainty of the torque key verification indicates the measurement reliability interval for p = 0,95. Marked W and given in% of measured value.
1.30. The relative value of the laboratory's best measuring capability is the best value of the expanded relative uncertainty that the laboratory can achieve. It is marked Wbmc and is given in% of the measured value.
1.31. The relative standard repeatability uncertainty is a partial verification uncertainty involving the repeatability of the torque key verification. It is marked wb 'and is given in% of the measured value.
1.32. The relative standard uncertainty of the best measurement capability of an etalon instrument is used to calculate the relative expanded uncertainty of the verified torque key and is obtained as a proportion of the relative value of the best measurement capability and the coefficient of expansion. It is marked wbmc and is given in% of the measured value.
1.33. The relative standard uncertainty of the mean value indicates a deviation of measured values from the mean. It is marked wM, and it is given in% of the measured value.
1.34. The relative standard uncertainty of the resolution of the torque key characterises the uncertainty caused by the limited resolution of the torque key. It is marked wr and is given in% of the measured value.
1.35. Effective degrees of freedom express the weight of repeatability in the total standard uncertainty of calibration and serve to determine the coefficient of expansion. It is marked veff and given in% of the measured value.
2 REQUIREMENTS FOR MOMENT KEYS
2.1. METHOLOGICAL REQUIREMENTS
2.1.1 Classification of torque keys
2.1.1.1. Indicative limit deviation
2.1.1.1.1. Moment keys of type I
The permissible deviation of the torque value shown on the torque key scale from the data on the etalon instrument scale shown at the same time shall be for:
(a) Classes A and D: ± 6% of the etalon instrument reading; and
(b) Classes B, C and E: ± 4% of the etalon instrument reading.
2.1.1.1.2. Moment keys of type II (limit torque keys)
The permissible deviation of the torque value set on the scale (classes A and D) or the nominal value (classes B and E) from the torque reading on the scale of the etalon instrument shall be for:
| a) třídy A a B: | ± 4 % údaje stupnice etalonového přístroje a |
| b) třídy D a E: | ± 6 % údaje stupnice etalonového přístroje. |
The permissible deviation of the set torque value from the reading on the scale of the etalon instrument shall be for:
| a) třídu C: | ± 4 % údaje stupnice etalonového přístroje a |
| b) třídu F: | ± 6 % údaje stupnice etalonového přístroje. |
For Classes C and F, the set torque value is equal to the arithmetic mean of ten readings on the etalon device.
2.1.2 Etalon apparatus
For the verification of torque wrenches, etalon devices having a valid calibration sheet and extended calibration uncertainty shall be used in the application range of W ≤ 1%.
Etalon devices shall be mounted on a sufficiently rigid frame. The electronic devices for larger moments (above 200 N.m) shall be equipped with a mechanized loading system.
2.2 TECHNICAL REQUIREMENTS
2.2.1. Construction
2.2.1.1 Assignment of connection quadrants
The size of the connection quadrant is determined by the maximum torque value of the torque key. The allocation shall be carried out according to the values given in Table 1.
Table 1: Rated size of connection quadrants
| Největší hodnota kroutícího momentu | Připojovací čtyřhran jmenovitá velikost |
|---|---|
| N•m | mm |
| 30 | 6,3 |
| 135 | 10 |
| 340 | 12,5 |
| 1000 | 20 |
| 2700 | 25 |
2.2.1.2 Specified measurement range
The measurement range for torque wrenches with a scale covers the area from 20% to 100% of the maximum torque of each torque wrench.
torque key scale I must be marked with zero value.
2.2.1.3. Scale
The increase in the moment of force between the two marks on the scale shall not exceed 5% of the largest value of the range. The differentiation of the scale r is the smallest figure that can be safely indicated on the scale (type I torque keys) or set (type II torque keys).
Torque measurement tools: type I
Figure 1. Examples of torque keys of type I
Tools to limit torque size: type II
Figure 2. Examples of torque keys of type II
2.2.2. Labels and marks
The torque keys shall be permanently and legibly marked with the following data:
(a) the largest value of the rated torque;
(b) the measuring unit;
(c) the purpose of loading (only for torque wrenches with one load wrenches); and
(d) if the manufacturer is a legal person, his or her business name and registered office and, if he or she has it, his or her name, surname and permanent residence shall be indicated in the case of the natural person involved.
3 TYPE APPROVAL
3.1. Procedure for type approval
3.1.1. Requirements for the documentation submitted
The applicant shall provide documentation in accordance with the specific legislation1).
3.1.2. Samples
At the request of the Type Test Executioner, the applicant shall deliver, free of charge, one sample of the torque key to perform the Type Test. This sample shall be kept with the Type Approval Authority.
3.1.3. Requirements for an etalon apparatus
The etalon apparatus referred to in paragraph 2.1.2 shall be used for the tests.
3.1.4 Environmental conditions
The normal conditions for placing an etalon apparatus shall be ensured during the tests. The test temperature shall be (23 ± 5) ° C.
3.1.5. Limit deviations of indication
The limit deviations of the indication are given in paragraph 2.1.1.1.
3.1.6. Test procedure
The test procedure is the same as for initial and subsequent verification (paragraph 4).
The tests shall be carried out in accordance with paragraph 4.
3.2. Type-approval certificate
The particulars of the type-approval certificate shall be laid down in a separate legislative act (2).
4 VERIFICATION
4.1 Etalon apparatus
The best measurement capability of an etalon instrument shall be less than or equal to ± 1 per cent of the torque measured.
Before carrying out the verification, the etalon device shall be adjusted and set to zero on the torque scale.
4.2. Verification temperature
The verification shall be performed after the temperature of the test torque key and calibration apparatus have been balanced at the ambient temperature (23 ± 5) ° C.
4.3. Verification progress
4.3.1. Before starting the verification, it shall be ensured that:
(a) for torque keys of the type: I display or display (for electronic torque wrenches) set to zero,
(b) for type I torque wrenches with a scale or a numerical deviation, the direction of view at reading the values perpendicular to the scale or the numerical deviation;
(c) for type II torque wrenches, a functional test of the torque wrenches is performed five times without reading values at the greatest or rated torque in the sense of loading; and
d) for single-arm torque wrenches the load force F is applied in the centre of the handle.
4.3.2. The torque wrenches shall be loaded in an etalon instrument with an increasing torque until the test torque value is reached (indication on the torque wrenching scale or the latch slip). After reaching approximately 80% of this value, the loading shall be carried out gently at intervals of one to four seconds commensurate with the torque value, unless otherwise stated by the manufacturer.
For torque wrenches of the type Even the torque test value exceeded, the test shall be repeated.
Type II torque wrenches shall have the relevant torque test value set, the test shall start at the lowest value.
4.4. Verification procedure
The torque key verification shall be carried out at three points of the torque key scale corresponding to 20%, 60% and 100% of the nominal torque of the torque key.
The verification of the torque key of type II, class B and E shall be carried out at the nominal torque value.
If the mark is not marked on the torque key scale for 20% of the largest torque, the test shall be carried out on the nearest lower marker.
The number of measurements in each sense of the torque and at each point of the scale verified shall be as follows:
(a) Type I, all classes: five consecutive times at each measuring point;
(b) Type II, Class A and D: five consecutive times at each measuring point;
(c) Type II, Class B and E: five consecutive times at nominal value; and
(d) Type II, Class C and F: 10 consecutive times at each measuring point.
The limit deviation of the indication for each verified point of the torque key scale shall be less than the values specified in paragraph 2.1.1.
4.5 Evaluation of verification
The verification shall be performed at the torque value set to the constant value of the torque key scale.
4.5.1 Determination of torque key sensitivity coefficient S
The torque key sensitivity coefficient S is calculated according to equation (1). The sensitivity coefficient is the ratio of the nominal value of the torque key force and the mean value of the measured values.
S = XM ^ 1
4.5.2 Determination of mean value from measured values of M
The mean value shall be calculated as the arithmetic mean of the n series of measurements for each torque measured according to the equation (2):
M?
4.5.3 Determination of repeatability of torque key b '
The repeatability of the torque b 'key is calculated according to the equation (3). The repeatability shall be calculated as the standard deviation from the set of n values measured for each torque value.
b '= ij = 1nMj-M ^ 2n-1. 3
4.5.4 Determination of the limit deviation of the torque key indication fq
The limit deviation of the indication is determined for torque wrenches for which the scale is indicated in torque units. It shall be calculated according to the equation (4) as the difference between the actual torque value and the mean value recorded for a certain degree of that torque.
fq = X-M. TO4
4.6 Verification sheet
The requirements of the certificate shall be laid down in specific legislation3). The verified torque key shall be indicated by the authority which carried out the verification by the official mark (4).
1) Decree No. 262 / 2000 Coll., which ensures uniformity and correctness of meters and measurements, as amended by Decree No. 344 / 2002 Coll.
2) § 3 of Decree No. 262 / 2000 Coll.
3) Annex 2 to Decree No. 262 / 2000 Coll.
4) § 6 of Decree No. 262 / 2000 Coll.
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Regulation Information
| Citation | Decree No. 66 / 2004 Coll., laying down requirements for control torque keys |
|---|---|
| Regulation Type | - |
| Author | - |
| Collection | Code of Laws |
| Date of Promulgation | 24.02.2004 |
|---|---|
| Effective from | 01.03.2004 |
| Effective until | - |
| Status | Valid |
The regulation text is for informational purposes only.
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