EP0925155A1

EP0925155A1 - Torque wrench

Info

Publication number: EP0925155A1
Application number: EP97932810A
Authority: EP
Inventors: Heinz Schönberger; Frank Humme
Original assignee: Saltus Werk Max Forst GmbH
Current assignee: Prosperas GmbH
Priority date: 1996-09-12
Filing date: 1997-07-11
Publication date: 1999-06-30
Anticipated expiration: 2017-07-11
Also published as: ES2150784T3; US6167788B1; DE19637067A1; WO1998010901A1; DE59702356D1; EP0925155B1; AU3622497A

Abstract

The invention concerns a torque wrench provided with an electronic evaluation device for values measured by sensors in order to detect the torque and an angle of rotation. According to the invention, in order to improve the transmission technology for determining the angle of rotation, a sensor takes the form of an acceleration sensor (9) for detecting the acceleration of the angle of rotation (α) whose measured values are chronologically integrated twice by the evaluation device (5) in order to determine the angle of rotation (α).

Description

00001 torque wrench

00002

The invention relates to a torque wrench

00004 an electronic evaluation device for measured values

00005 of sensors for detecting the torque and one

00006 angle of rotation.

00007

Such a torque wrench is from EP 0 133

00009 557 known. It is with the torque wrench there

00010 sel provided a microprocessor with keyboard over

00011 the desired data such as setpoints, limit values,

00012 or the like for the tightening process as a default

00013 can be entered. According to these guidelines

00014 the tightening process z. B. monitors a screw.

00015 When certain limit values are reached, a

00016 automatic saving of these values. As

00017 there has been the encoder technology for the

00018 measured values of the angle of rotation measuring device highlighted,

00019 which consists of a pulse wheel and a reflex probe

00020 essentially exists. It is very much this encoder technique

00021 complex and example with regard to pollution

00022 very vulnerable. In addition, the arrangement

00023 impulse wheel / reflex probe the geometry of the key

00024 essentially determined.

00025

00026 This poses the technical problem of

00027 to improve the technology for detecting the angle of rotation,

00028 in particular without twisting against each other

00029 bar arranged sensor components.

00030

00031 This technical problem is caused by the subject

00032 of claim 1 solved, the focus being on

00033 that a sensor as an acceleration sensor for detection

00034 of the angular acceleration is formed, the

00035 measured values the evaluation device for determining the 00036 angle of rotation integrated twice in time. The kind of

00037 time integration depends on the total

00038 design of the evaluation device and in particular also

00039 from the output of the measured values of the acceleration sensor

00040 sors. So the integration by means of differential amplification

00041 ker done in a conventional manner when

00042 the measurement values are evaluated analogously. Is a

00043 microprocessor provided, for example, a

00044 evaluation also take place digitally and stand for this

00045 different numerical integration methods available

With which the microprocessor can then be programmed

Is 00047. Suitable acceleration sensors are known and

00048 commercially available. Such applications are preferably used.

00049 acceleration sensors at a defined distance

00050 to the swivel axis in the torque wrench

00051 net and which the pivot axis of the torque

00052 finally serves as a virtual benchmark. This Ab-

00053 stand depends on the type of accelerator used

00054 and then align it. In the opposite

00055 set of acceleration sensors for the detection of

00056 angular accelerations, which are ring-shaped around a

00057 axis of rotation are arranged, for example,

Arrangement drew the advantage that there is no measurement here

00059 between components that are fixed to the rotary axis and to the key

00060 is done. Below is the deflection angle

00061 part of the angle of rotation to understand which

00062 of defined initial conditions of a zero

00063 kellage such as a spatial location of the

00064 torque wrench to count to a housing

00065 starts and with the end of the tightening process or

00066 control process also ends. This will

00067 in addition to measuring the torque also by the deflection

00068 angle the secure tightening of a screw, for example

00069 found. Such a zero angle position can

00070 torque key can be entered manually, for example 00071 den. Mostly, however, is a torque wrench

00072 type mentioned to control the suit of

00073 for example screws for a large number of similar

00074 eng fittings used in series production.

Here, it has proven to be expedient that

00076 the evaluation device with a starting torque

00077 is preprogrammable and a deflection angle from the

00078 chen of the starting torque is determined. hereby

00079 is first the detection of the torque with the

00080 Detection of the angle of rotation to determine the deflection angle

00081 kels linked. Here with the result that the beginning

00082 the determination of the deflection angle

00083 is. According to the invention, the acceleration

00084 sensor an angular acceleration which is

For example, 00085 a screw both positive and

00086 can also be negative, but still using the screw

00087 a positive torque is tightened. However, will

00088 when using a ratchet or ratchet the torque

00089 ment or the angular velocity negative, namely

Counter to the return of the torque wrench

00091 of the tightening direction, this may be

00092 key swept angular range not taken into account

00093 as it does not tighten the screw

00094 contributes. It is therefore expedient that measured values of the

00095 acceleration sensor only in a specifiable rotation

00096 direction can be evaluated. In a further embodiment

It is provided that the evaluation device with each

00098 a lower and an upper limit for the torque

00099 ment and a deflection angle is preprogrammable and

00100 that the evaluation device between the respective

00101 Displays actual values lying within the limit values. Hereby

00102 there is a double check of the tightening process

00103 visibly reaching a predetermined area

00104 both the torque and the deflection angle.

00105 It can further be provided that the evaluation 00106 device indicates that the lower limit 00107 of the torque and / or the deflection angle 00108 has already been exceeded. This indicates to the user that the 00109 process of tightening a screw, for example, 00110 is nearing the end and that he now also has to monitor the upper limit values 00111 such that they are not exceeded by 00112. If the upper limit value of the torque and / or the deflection angle is exceeded, 00114 is likewise indicated by the evaluation device, 00115, which signals that this tightening process 00116 has not been properly completed. 00117 has proven to be expedient to carry out such a display of 00118 reaching or exceeding limit values by means of 00119 at least one light-emitting diode. 00120 offers a variety of display options; 00121, for example, can be signaled by a color change or a 00122 flash if the limit values of the torque or the deflection angle are exceeded. 00124 Reached end values are shown together in the usual way on a 00125 LCD display or the measurement mode can also be switched and a switchable, 00127 alternative display of the end torque or the end deflection angle. These end values can be stored by the 00129 microprocessor, transferred to a computer via 00130 an appropriate interface or immediately output to a printer. 00132 00133 The invention will be explained in more detail with reference to the drawing, in which it is only shown by way of example and in principle 00135. In the drawing: 00136 00137 FIG. 1 shows the torque wrench according to the invention and its essential components, 00141 FIG. 2 is a flowchart which is used to explain the first 00142 phase of a tightening process after switching on 00143 of the torque wrench, 00144 00145 FIG. 3 shows a flowchart for determining the deflection angle and 00147 00148 FIG. 4 plots the rotation angle over the torque 00149 or deflection angle. 00150 00151 Fig. 1 shows the essential components of a torque wrench 1 according to the invention. For tightening a 00153 screw, a nut or the like around a rotary axis 00154 se 2, it has an insertion tool 3, which is held on the 00155 torque wrench 1 via a conventional plug-in socket 00156. 00157 00158 contents of a handle 4 is guided to the Drehmomentschlüs00159 sel 1 about the axis 2 of rotation over an angular range _o 00,160th With reference to tightening 00161 of a screw, for example, a clockwise 00162 rotation angle and a 00163 torque applied in this direction are counted positively. It goes without saying that the 00164 counting direction can be reversed, for example, for screws with a left-hand thread. The angle 00166 speed geschC and the angular acceleration oC in 00167 clockwise also count accordingly. 00168 00169 The torque wrench 1 has an electronic 00170 evaluation device 5 for evaluating measured values supplied by Senso00171 for the acquisition or calculation 00172 of the torque M and the angle of rotation o. A key 00173 field 6 is used for pregraming, for example, a 00174 microprocessor of the evaluation device and in particular 00175 re for entering limit values with respect to the rotation or 00176 deflection angle β or the torque M. Reaching 00177 or exceeding such limit values is indicated by a 00178 LED line 7. End values of the torque M or 00179 of the torque or are shown on a 00180 LCD display 8. 00181 00182 Measurement and evaluation of the torque M is carried out according to 00183 known methods. 00184 00185 For the detection of the angle of rotation o and determination of the 00186 deflection angle β, an acceleration sensor 9 is provided for the torque wrench 1 according to 00187 of the invention for detecting 00188 the angle of rotation acceleration oC, which 00189 within the torque wrench 1 at a defined distance s from the axis of rotation 2 is located 00191. The pivot axis 2 serves the acceleration sensor 00192 9 as a virtual fixed point about which it is then also pivoted 00193. This distance s is essentially 00194 determined by the design of the acceleration sensor 9 used, which is commercially available. 00196 00197 Via a plug connection 10 the torque wrench 00198 sel 1 can be connected via a conventional interface, for example 00199 to a computer 11 and / or a printer 12 for 00200 logging of the measurements. 00201 00202 Based on the flow diagrams according to FIGS. 2 and 3, 00203 the evaluation of the measured values by the evaluation device 5 is explained in more detail below. After step 15 00205 of switching on, a self-test and a zero adjustment is carried out automatically in step 16 by the evaluation device 00206 5. Following this, provide 00208 if calibration of the torque wrench 1 00209 is to be provided. In addition to the known calibration of the Momen00210 ten measuring device, a separate calibration 00211 tion for the rotation angle measurement. 00212 can be done, for example, by applying the torque 00213 key 1 and manually setting the memory for the 00214 angle of rotation to the value zero. 00215 The torque wrench 1 is then pivoted about its 00216 axis of rotation 2 over a defined angle range 00217, which is then also to be indicated by the evaluation device 00218. 00219 00220 After step 16, which can possibly also be jumped to 00221, 00222 sets the parameters for the measuring process in step 17. Regardless of the 00223 sequence, these are the starting torque 00224 Mε. Of course, the starting torque Ms 00225 can also be set to zero, which means that the rotation angle 001 and the deflection angle β coincide. Usually 00227, however, a starting torque M greater than zero 00228 is selected here, which is specified by the application 00229. Furthermore, a lower and an upper limit value 00230 for the torque are to be set as minimum and maximum values Mmi.n, Mmax 00231, which define the torque range, in 00232 which, when a screw or the like is tightened, the final value of the torque reached 00233 as OK 00234 is located. 00235 00236 In the same way, minimum and maximum values are ß. ^*** 'l min, 00237 P to specify the angular range in which the deflection max. ³ 00238 count, beginning when the start 00239 torque Ms has reached, at the end of the measurement. 00240 00241 This setpoint specification also includes 00242 for the measurement itself. By switching off the 00243 or another measuring device, for example, the 00244 torque M can be measured or the angular acceleration o can also be measured. 00246 After setting the parameters in step 17, 00247, after applying the torque key, for example 00248 manually or controlled by one of the sensors, begins with 00249 measuring the torque M and the angular acceleration 00250 gung oi. These measurements according to steps 18, 00251 19 take place continuously over the entire tightening process, for example of a screw. In step 20, 00253 the measurement result of the torque is checked to see whether it is greater than or equal to the starting torque M 00255. As long as the determined torque is less than 00256 this value, the torque measurement is continued as normal 00257. 00258 00259 The result of the acceleration measurement O is also checked regularly in 00260 step 21, namely to determine whether the direction of rotation coincides with the tightening direction of a nut, for example. According to the specifications met here, the angular velocity ό £ 00264 must be greater than zero. This query criterion can be seen here alternatively, since, for example, the occurrence 00266 of a negative torque would also indicate 00267 that the direction of rotation was reversed, for example 00268 when using a ratchet or ratchet. If there is a 00269 backward movement of the torque wrench 1, 00270 the measured acceleration value oi is no longer processed 00271 and in particular not added to the angle of rotation in 00272 tightening direction. However, the acceleration measurement o continues as normal. 00274 00275 If it is determined in step 21 that there is a swivel movement of the torque wrench 1 in the tightening direction 000077, ie here that the angular velocity c is greater than zero, the 00279 angular acceleration OIL is integrated twice over time. 00280 different methods are available for this. With an analog 00281 gene integration, for example via differential amplifier 00282, the measured values are continuously evaluated. 00283 Programming 00284 offers an alternative possibility, for example of a microprocessor which is present in evaluation circuit 5 and which then uses individual measured values as 00286 base values for numerical integration. 00287 Here, too, different methods are possible again. For example, the microprocessor can save all measured values as 00289 base values and use this to calculate the 00290 angle of rotation oC for the current, last measurement. Alternative methods allow that integration is only carried out over the last time interval Δt 00293, namely from a previous time interval 00294 t - Λ t to time t, where t is the current 00295 le time and Δ t is the time span for the penultimate 00296 measurement means. The result Δ. L this integrati00297 on is added to the previous integration result 00298. Such a numerical integration procedure is used here in the following description of the 00300 measurement evaluation. 00301 00302 If it is determined in step 20 that the starting torque M has been exceeded, the determination of the deflection angle 00 begins, cf. also FIG. 4. Here, too, 00305 are alternative methods. Thus, as preferred here before 00306, the current numerical value of oL, ie the angle of rotation swept up to 00307 at this time, can be set to zero in 00308 step 23. Since the acceleration measurement is continued continuously, 00310 stored intermediate values can be used, for example, 00311 and the acceleration measurement 00312 can still be determined by integrating the deflection angle β be00313. Alternatively, it would be possible to save the 00315 value of oC that is present when the starting torque M is exceeded and to determine the final value of the Subtract 00316 angle measurement to determine the deflection angle ß 00317. 00318 00319 It is also clear at this point that the 00320 acceleration measurement must begin with the torque measurement at 00321 of the described embodiment. If 00322 the acceleration measurement tx would only begin when the 00323 starting torque M was exceeded, then the starting conditions for the integration would have to be additionally determined by measuring the 00325 angular velocity όc00326. Although this is possible in principle, 00327 would mean another sensor 00328 or a further measurement or calculation for the torque wrench 1. 00329 00330 The aim of tightening a screw or 00332 or the like using a torque wrench 1 according to the 00331 invention is that the torque between predetermined limit values Mmi.n, Mmax or the deflection angle 00334 between limit values ßr mi.n, ßrmax ultimately after tightening ^ 00335 the screw come to rest. This is explained further in 00336 on the basis of the flow chart according to FIG. 3. After the starting torque Ms 00337 is exceeded, both the 00338 torque measurement 18 and the acceleration measurement 19 continue to be carried out unchanged. The evaluation 00340 of the acceleration measurement © C is also carried out 00341 according to steps 21, 22, but in the current memory no longer a summation of the rotation angle _> L, but after step 23 a summation of the 00344 deflection angle β now takes place, as explained above 00345 tert. 00346 00347 In a step 30, a query is then made as to whether the 00348 current values of the torque M or the deflection angle 00349 are in the predetermined limit ranges according to FIG. 4 00350. Is this, as initially, by too small values 00351 for the torque M and the deflection angle ß not

Given 00352, the query in step 31 is whether the

00353 upper limit values Mmax, from the current values

00354 were exceeded. Are the current values M, ß

00355 is still below the specified end range, so is

00356 this is naturally not the case and the torque

00357 solution M and acceleration measurement ov remain unchanged

00358 continued. Step 31 is an alternative to

00359 can only be predicted at a later point in time, namely

00360 if the lower limit values Mmi.n, | ß ^J mι.n exceeded

00361 th. This step 31 would then be in the

00362 "Yes" Connect branch to step 30. This could

00363 computing capacity can also be saved if necessary. 00364

00365 If it is determined in step 30 that a current

00366 Measured value M, ß in the specified interval of the lower

00367 and the upper limit values, then in step 32 a

00368 signal triggering, for example, of LED line 7

00369 made that a measurement result in the desired

00370 th range. Depending on the linkage of the queries

00371 in step 30 can trigger such a signal for

00372 each step individually or can be one

00373 The signal is only triggered if both

00374 criteria are met. This last signal trigger

00375 indicates to the user that the tightening process is

00376 has ended richly. If the display is separate

00377 signals to the user that at the end of the suit

00378 ganges with increased attention also reaching

00379 of the other criterion. Still

00380 is then also the torque measurement M and

00381 acceleration measurement oC still carried out. 00382

00383 Is the correct end of the

00384 signals the tightening process, the user is in the

00385 Rule relieve torque wrench 1. Accordingly 00386 the torque M, the angular acceleration o and the 00387 angular velocity όi assume the value zero. If 00388 is determined by the evaluation device 5 in step 33 00389, it ensures that the end values 00390 are displayed, for example on the LCD display 8. These end values 00391 can also be stored by the evaluation device 5, for example up to 1,000 pieces. 00393 Alternatively, these end values can also be transferred to a 00395 computer 11 or printer 12 immediately or 00394 after storage, as explained at the beginning. However, if the evaluation device 5 ascertains in 00396 step 33 that a torque M and / or a 00398 angular velocity oc is still present in the tightening direction, the torque measurement M and 00400 the acceleration measurement [00400] are still carried out. In particular, in such a case, in which the user inadvertently, for example, continues to tighten a screw, 00403 step 30 determines that the current values 00404 M, ß are no longer within the specified interval, 00405 but according to step 31 the specified ones upper 00406 limits Mmax and / or ßr max have been exceeded. 00407 In this case, the signal is triggered "incorrectly" in step 35. In particular if the maximum limit values are exceeded incorrectly, 00410 has also proven to be expedient to use an acoustic 00411 display, for example a buzzer. 00412 00413 According to step 33 it is determined in a step 36 00414 whether the tightening process has ended and 00415 then correspondingly displays a final value 37 00416 "faulty" or the measuring process is continued as before 00417. 00418 00419 All features disclosed are essential to the invention. In 00420 the disclosure of the application is hereby also 00421 disclosure content of the associated / attached priori

00422 full documents (copy of pre-registration)

00423 was included, also for the purpose of characteristics of this

00424 documents in claims of this application with

00425 to record. 00426

Claims

00427 claims 00428 00429 1. Torque wrench with an electronic Auswer00430 teventer for measured values from sensors for detecting 00431 the torque and an angle of rotation, characterized gekenn00432 that a sensor is designed as an acceleration sensor (9) 00433 for detecting the angle of rotation acceleration (,), whose Measured values, the evaluation device (5) 00435 for determining the angle of rotation (oC) integrated twice in time 00436. 00437 00438 2. Torque wrench according to claim 1 or in particular 00439 re thereafter, characterized in that the acceleration sensor (9) is arranged at a defined distance (s) from the 00441 axis of rotation (2) in the torque wrench (1) 00442 and the axis of rotation ( 2) the acceleration sensor (9) 00443 serves as a virtual fixed point. 00444 00445 3. Torque wrench according to one or more of the 00446 preceding claims or in particular according thereto, 00447 characterized in that the evaluation device (5) 00448 can be preprogrammed with a starting torque (M) 00449 and a deflection angle (β) from reaching the start 00450 torque (ms) determined. 00451 00452 4. Torque wrench according to one or more of the 00453 preceding claims or in particular according thereto, 00454 characterized in that measured values of the acceleration sensor (945) are evaluated 00456 only in a predeterminable direction of rotation 00456 or counting direction of the angular velocity (β £). 00458 00459 5. Torque wrench according to one or more of the 00460 preceding claims or in particular according thereto, 00461 characterized in that the evaluation device (5) 00462, each with a lower and an upper limit value 00463 for torque (Mmi.n, Mmax) and an angle of deflection 00464 (ßrmi ■ n, ßrmax) Vorp ^ rog ^a rammierbar and that the evaluation 00465 tevorrichtung lying between the limit values actual Who shows 00466 te (M, ß). 00467 00468 6. Torque wrench according to one or more of the 00469 preceding claims or in particular according to it, 00470 characterized in that the evaluation device (5) 00471 exceeding the lower limit of the torque (Mmi.n) and / or the deflection angle (ß \ min 00474. 00474 00475 7. Torque wrench according to one or more of the 00476 preceding claims or in particular according thereto, 00477 characterized in that the evaluation device (5) 00478 the exceeding of the upper limit value of the torque (M IUci-C) and / or of the deflection angle (ß \ TTICT-X.) 00480 00481 8. Torque wrench according to one or more of the 00482 preceding claims or in particular according thereto, 00483 characterized in that the display is followed by at least one 00484 one light-emitting diode (7). 00485 00486 9 Torque wrench according to one or more of the 00487 preceding claims or in particular according thereto, 00488 dadu rch characterized that the evaluation of the measured values 00489 takes place analogously. 00490 00491 10. Torque wrench according to one or more of the 00492 preceding claims or in particular according thereto, 00493 characterized in that the evaluation of the measured values 00494 is carried out digitally.