EP1038638A1 - Torque wrench - Google Patents

Abstract

A signal is transmitted by a wrench force sensor (42) and a workpiece identification device (36) generates an identification signal, both of these signals being sent to a control device (40). The wrench force signal is compared in the control device with at least one pre-determined or pre-determinable reference signal, and then based on the information from the wrench force and identification signals, the device generates a screw force control signal. An Independent claim is also included for the testing method using this wrench.

Description

The invention relates to a torque wrench for testing a torque in a screwing process on a workpiece and a method for Testing a torque as defined in the respective claims 1 and 11 are described.

In order to check a tightening torque of a screw connection, conventional Torque wrench used. Such torque wrenches allow on the one hand a check whether the tightening torque is equal or greater than a predetermined reference torque and, on the other hand, should not be the case until the reference torque is reached continue to attract. In particular, there are so-called kink keys Use where the torque introduced by a mechanism is limited and the user can hear and feel the achievement of Reference torque is displayed. Here, the reference torque, at which the kink key triggers, factory-set.

Are such conventional torque wrenches in the assembly or Manufacturing technology used, however, serious problems arise that in a lack of security against incorrect operation as well as in a restricted Area of application. This is how these torque wrenches support the user prior to starting a torque test, not whether the key is suitable for this at all, with which the user switches to a manual and error-prone control is forced using a checklist. When a If a large number of screw connections is to be checked, the user must check the test results also log it manually and make sure there is no test was ignored. This is particularly problematic when screw connections with different reference torques should be checked, because here the torque wrench used must also be recorded.

It is an object of the invention to provide a torque wrench for testing a To provide torque on a workpiece, the improved error safety and has simple operating properties and preferably in simple way for torque tests with different reference torques can be used. It is also an object of the invention to specify the appropriate procedure for torque testing.

This task is accomplished using a torque wrench as well as a procedure the features specified in claim 1 and claim 11 solved. Preferred Embodiments are the subject of the dependent claims.

• einen Drehmomentsensor zur Ausgabe eines Drehmomentsignals,
• eine Werkstückidentifizierungseinrichtung zur Erzeugung eines Identifizierungssignals, das dem jeweiligen Werkstücken zugeordnet ist, und
• eine Steuereinrichtung, die mit dem Drehmomentsensor und der Werkstückidentifizierungseinrichtung in Signalverbindung steht,

wobei die Steuereinrichtung zu einem Vergleich des Drehmomentsignals mit zumindest einem vorbestimmten oder vorbestimmbaren Referenzdrehmomentsignal und zu einer Erzeugung eines Verschraubungskontrollsignals auf Grundlage des Identifizierungssignal und dem Drehmomentsignalvergleich ausgelegt ist.According to the invention comprises a torque wrench for checking a torque during a screwing process on a workpiece

• a torque sensor for outputting a torque signal,
• a workpiece identification device for generating an identification signal which is assigned to the respective workpieces, and
• a control device which is in signal connection with the torque sensor and the workpiece identification device,

wherein the control device is designed to compare the torque signal with at least one predetermined or predeterminable reference torque signal and to generate a screw connection control signal based on the identification signal and the torque signal comparison.

This advantageously results in a high level of error and operational reliability Test of tightening torques of screw connections reached and at the same time the prerequisites for simple, automated logging of test results created. So includes the tightening control signal advantageously the result of the torque test, i.e. the result, whether the reference torque has been reached, while the tested one Workpiece, e.g. whose serial or part number is identifiable.

According to a preferred embodiment, the torque wrench comprises a signal output device for outputting the screw control signal and the identification signal to one of the torque wrenches spatially Separately provided signal receiving device with the control device is in signal connection and is preferably a non-contact electromagnetic Signal transmission designed. This advantageously makes it possible the result of every single torque test of the workpiece transmitted to the external signal receiving device by radio and thus allows a particularly simple and fail-safe monitoring and logging of the Checking processes with the torque wrench.

According to a further preferred embodiment, the torque signal the reference torque signal and the tightening control signal electrical, magnetic or electromagnetic signals and the control device is a microprocessor computer. Although it is also an exclusively mechanical one Processing and comparison of the torques and output of the signals possible, but will be advantageous for reasons of cost and functionality electrical or electronic components used.

According to a further preferred embodiment, the signal output device an electromagnetic transmitter. This can be, for example act as a radio transmitter operating in a generally approved Frequency band (e.g. at 27MHz, 433MHz) the signals to an external receiving device sends. This has the advantage that no disturbing electrical Cables for external signal transmission are necessary.

According to a further preferred embodiment, the workpiece identification device a code reader, in particular a bar or bar code reader. In particular, the workpiece identification device can be a pattern recognition device be the predetermined graphic pattern in one-to-one Way can assign a workpiece. However, it is also possible to use electronic Use transponder systems, preferably those that are non-contact can be read out electromagnetically.

According to a further preferred embodiment, the torque wrench a buckling function, with the torque sensor on a permanent magnet attached to a torque rod or buckling rod and a magnetic switch, in particular a reed switch or an induction switch comprises and the magnetic switch for detecting an offset of the Permanent magnets when the torque rod kinks due to a Reaching a predetermined reference torque relative to the magnetic switch is trained. This makes it possible in a particularly simple manner to generate an electric torque signal which indicates that the reference torque has been reached displays. At the same time, the advantages of a kink wrench maintained, especially the clearly audible and noticeable triggering as soon as that Reference torque is reached.

According to a further preferred embodiment, the torque sensor a strain gauge sensor, preferably in the form of a strain gauge bridge, which is based on an initiated torque by bending responding torque rod of the torque wrench is arranged. The The torque rod is thus designed as a bending rod. By the bend the torque rod undergoes a change in the geometry of the strain gauges, which results in a change in resistance. Advantageously can each such change in resistance by means of the control device in a clear Way the size of the corresponding initiated torque be assigned.

According to a further particularly preferred embodiment, one is a tool holder of the torque wrench opposite end the torque rod, a locking device arranged which the Torque bar unlocks when it receives an unlock signal from the controller receives. This allows using a single torque wrench screw connections with different assigned in a simple manner Check reference torques without complex mechanical readjustment a trigger torque setting.

According to a further preferred embodiment, the locking device comprises a ferromagnetic enclosed by a magnetic coil Locking bolt, which is in a locking recess in the torque rod can be inserted to lock them, and by applying a current the magnetic coil can be taken out of this. This makes it possible advantageously, a kink key function of the torque wrench in easy to combine with different reference torques.

According to a further preferred embodiment, the torque wrench comprises a control signal receiving device which is connected to the control device in Signal connection is established and to receive control signals from an external Control device is designed, preferably by non-contact electromagnetic Transmission. This advantageously enables bidirectional Signal transmission between the torque wrench and the external control device, making the torque wrench more efficient and flexible to use is. In particular, the control signals of the external control device be dependent on the identification signal and for example one for the Workpiece individually adjusted reference torque signal included.

(a) Detektieren eines Werkstücks bzw. einer Werkstückkennzeichnung, insbesondere eines entsprechenden Codes, vorzugsweise eines Barcodes;

(b) Erzeugen eines dem Werkstück entsprechenden Identifizierungssignals;

(c) Prüfen des Drehmoments der Verschraubung des Werkstücks und Erzeugen eines entsprechenden Drehmomentsignals;

(d) Vergleichen des Drehmomentsignals mit einem vorbestimmten oder vorbestimmbaren Referenzdrehmomentsignal;

(e) Erzeugen eines Verschraubungskontrollsignals auf Grundlage des Identifizierungssignals und des Drehmomentsignalvergleichs.

Das Verschraubungskontrollsignal beinhaltet alle notwendigen wesentlichen Daten einer Drehmomentprüfung einer Verschraubung und ermöglicht somit vorteilhafterweise eine fehler- und betriebssichere Prüfung von Anziehdrehmomenten komplexer Werkstücke. Insbesondere beinhaltet das Verschraubungskontrollsignal das Drehmomentprüfungsergebnis, d.h. das Ergebnis, ob das Referenzdrehmoment erreicht wurde.According to the invention, a method for testing a torque during a screwing process on a workpiece, in particular using a device according to the invention, comprises the following documents in this order:

(a) detecting a workpiece or a workpiece identification, in particular a corresponding code, preferably a bar code;

(b) generating an identification signal corresponding to the workpiece;

(c) checking the torque of the screw connection of the workpiece and generating a corresponding torque signal;

(d) comparing the torque signal with a predetermined or predeterminable reference torque signal;

(e) generating a tightening control signal based on the identification signal and the torque signal comparison.

The screw connection control signal contains all the necessary essential data for a torque test of a screw connection and thus advantageously enables a fault-free and reliable test of tightening torques of complex workpieces. In particular, the tightening control signal contains the torque test result, ie the result of whether the reference torque has been reached.

According to a preferred embodiment of the method, the invention comprises Proceed the following document the output of the screw connection control signal to a receiving device, preferably by a non-contact electromagnetic transmission. This makes it easy Monitoring and logging of torque testing processes by a external monitoring and control device possible, which leads to another Increases error and operational safety.

According to a further preferred embodiment of the method immediately after writing (b) the identification signal to a receiving device issued, preferably by a non-contact electromagnetic Transmission. This allows before the actual torque test step is started, a preliminary check is advantageously carried out to determine whether this workpiece is to be tested at all and which test parameters note.

According to a further preferred embodiment of the method, the Reference torque signal depending on the generated identification signal, if necessary after reconfirmation by the receiving facility, fixed. This advantageously enables the identified workpiece automatically assign the corresponding reference torque, preferably without the user having to use test and parameter lists got to.

Figur 1

eine schematische Schnittansicht einer ersten Ausführungsform eines erfindungsgemäßen Drehmomentschlüssels; und

Figur 2

eine schematische Schnittansicht einer zweiten Ausführungsform eines erfindungsgemäßen Drehmomentschlüssels.

The invention is described below by way of example using preferred embodiments with accompanying drawings. It shows:

Figure 1

is a schematic sectional view of a first embodiment of a torque wrench according to the invention; and

Figure 2

is a schematic sectional view of a second embodiment of a torque wrench according to the invention.

In a simplified, schematic sectional side view, one in FIG first embodiment of a torque wrench according to the invention shown. The torque wrench 10 includes a housing body 12 which has an integrally formed handle 14 at its rear end. In the area of the handle 14 is a battery recess in the housing body 12 Inclusion of a battery 16 provided in the longitudinal direction of the rear end can be inserted into the housing body 12. The battery recess is closed by a battery cover 18 on a rear End face 17 of the housing body 12 is attached.

On one of the rear end faces 17 in the longitudinal direction of the housing body 12 opposite end is a torque rod bushing 20 provided in the housing body 12 through which a torque rod 22nd is partially inserted into a torque rod recess 24. On one extending in the longitudinal direction from the housing body 12 End of the torque rod 22 is a tool holder head 25 for arrangement a screw nut is provided, which is designed as a 90 ° ratchet head. The torque rod 22 has in the area of the torque rod bushing 20 has a pivot pin bore that is perpendicular to the longitudinal Axis of the torque rod 22 extends parallel to the plane of the drawing. By the pivot pin bore is inserted a pivot pin 26, the ends of which in the housing body 12 are fixed and which the torque rod 22nd swiveling.

Between a rear end face 28 of the torque rod 22 and one Trigger torque setting 30, a spring 32 is arranged, which is the torque rod 22 acted upon by a longitudinal spring force. The The size of the spring preload can be adjusted by setting the trigger torque 30 can be adjusted by a spring contact surface 34 of the triggering torque setting 30 is moved in the longitudinal direction to the compression of the Control spring 32, which is indicated by the arrow x. To do this, the Battery cover 18 and battery 17 are removed so as to access the to get the rear side of the trigger torque setting. The amount of spring preload determines the reference torque of the torque wrench 10, i.e. the torque at which the key is triggered by a "kink". The Triggering or kinking occurs precisely when one is caused by the reference torque predetermined buckling force in the key 10 by an in a testing screw connection initiated torque is reached. The for Longitudinal axis of the torque rod 22 and normal to the plane of the drawing Buckling force acts on the rear end face 28 of the torque rod 22. Forces that are less than this predetermined buckling force, the spring 32 compensate. However, if the amount of the buckling force is reached, a jerky pivoting of the torque rod 22 in the torque rod recess 24 until an edge of the rear face 28 is the inner surface touches the torque rod recess 24. Typically is the offset of the rear face 28 about 3-4mm. This triggering the Torque wrench 10 is audible and noticeable kinking noise accompanied.

According to the invention are on an outer surface of the housing body 12 on the Handle 14 in the longitudinal direction opposite side as a workpiece identification device serving barcode reader 36, one as a signal output device serving radio transmitter 38 and serving as a control device Microprocessor computer 40 arranged side by side, one below the other and with the battery 16 are electrically connected. The barcode reader 36 is oriented such that his preferred reading direction parallel to the longitudinal axis of the Torque rod 22 and the housing body 12 extends and forward in Direction of the tool holder head 25 is directed. The detected solid angle of the barcode reader 36 is shown schematically by the beam.

Furthermore, on the outside of the housing body 12 is a magnetic switch serving reed switch 42 arranged. On the torque rod 22 is a Hard magnet 44 attached so that it is opposite the reed switch facing, i.e. lies on a line from the longitudinal axis of the torque rod runs to the reed switch 42. The reed switch 42 is connected to the Microprocessor computer electrically connected.

The following is the operation and operation of the torque wrench according to the first embodiment of the invention:

First, the worker or user reads one using the barcode reader 36 Barcode of a workpiece (not shown). The barcode can, for example include the serial or part number of the workpiece. The so won Identification signal of the workpiece to be tested is subsequently called electronic signal passed to the microprocessor computer 40 to be there possibly to be processed.

The possibly further processed identification signal then becomes the Radio transmitter 38 transmit electrically, which then this to a not shown Signal receiving device provided separately from the torque wrench sends as an electromagnetic signal without contact. As transmission frequencies come in particular the freely accessible frequency ranges 27MHz and 433MHz. The signal receiving device is in signal connection with an external control device (not shown) that the Identification signal evaluates and stores. Is the sent identification signal with a predetermined one stored in the external control device Signal, is the torque wrench used by the user 10 suitable for predetermined screw connections of the identified To check the workpiece. In this case the torque test is released, the user through an acoustic and / or optical signal is shown. The display can be done by a display device (not shown) take place, which is connected to the external control device.

Alternatively, the acoustic and / or optical release signal can also be given by a provided device (not shown) (for example an LED and an acoustic buzzer) in the torque wrench. In this case the radio transmitter 38 must also have a radio receiver (control signal receiving device, not shown) to include a bidirectional non-contact Data transmission between the torque wrench 10 and the external Allow signal receiving device. The external control device sends a corresponding release signal to trigger the release Radio receiver of the torque wrench. This signal is sent to the microprocessor computer 40 forwarded, which then the (not shown) release indicator of the torque wrench.

After approval, the user begins checking the tightening torque the first predetermined screw connection of the workpiece usual use of the torque wrench 10. If the predetermined Reference torque is reached, the torque wrench "kinks", i.e. the Torque bar or buckling bar experiences a jerky swiveling as described above. This pivoting has the consequence that the hard magnet 44 is offset relative to the reed switch 42, with which this is actuated. The reed switch 42 thus functions together with the hard magnet 44 as Torque sensor and delivers a torque signal to the microprocessor computer 40 is transmitted electrically.

Is a torque signal of the reed switch from the microprocessor computer 40 42 received, the predetermined reference torque was reached and successfully checked the screw connection. The microprocessor computer 40 then causes radio transmitter 38 to apply a tightening control signal the signal receiving device sends. This signal is from the external Control device evaluated and saved.

If the workpiece to be tested does not have all of the predetermined screw connections checked, the external control device can be a corresponding Output warning or error signal and possibly in addition to rework prompt. Because the result of each tightening operation is automatic in this way is logged and checked for each workpiece to be checked, a high Failure safety achieved. Not all of the predetermined test procedures are successful completed, the workpiece is not released.

Figure 2 is a schematic side sectional view of a second particular preferred embodiment of the torque wrench according to the invention. Compared to the first embodiment shown in FIG. 1, they have the same or similar features have the same reference numerals and are not used in the following described again.

On the rear end face 28 of the torque rod 22 is a locking body 52 attached with a locking recess 54 such that the Longitudinal axis of the torque rod 28 with the central axis of the circular cylindrical locking recess 54 coincides. In the locking recess 54 is a circular cylindrical locking bolt 56, the Outer diameter approximately the inner diameter of the locking recess 54 corresponds, insertable. The central axis of the locking bolt 56 also coincides the longitudinal axis of the torque rod 22 together when there is no torque is initiated. The locking bolt 56 is preferably ferromagnetic.

A section of the locking bolt facing away from the locking body 52 56 is surrounded by a magnetic coil 58, which has an inner diameter has, which corresponds approximately to the outer diameter of the locking bolt 56. The magnet coil 58 is arranged in the housing body 12 in such a way that its longitudinal axis with the longitudinal axes of the locking bolt 56 and the torque rod 22 coincides if no torque is introduced becomes. A return spring 60 is between the rear face of the locking bolt 56 and a spring contact wall 62 of the magnetic coil 58 in this way arranged that they have a longitudinal restoring force on the locking bolt 56 exercises in the direction of the locking recess 54. The locking body 52, locking bolt 56, solenoid 58, return spring 60 and Spring contact wall 62 together form a locking device 64, the Operation will be described later.

On the torque rod 22, which is designed as a bending rod, strain gauges 66 attached such that an operational bend the Torque rod 22 by a introduced into the torque wrench 50 Torque to change the electrical resistance of the strain gauges 66 leads. Secondary influences, especially temperature influences, to be able to rule out the resistance of the strain gauges 66 these are electrically connected in a bridge circuit. The exit of the strain gauge bridge 66 is electrically connected to the Microprocessor computer 40 connected. There is one in the microprocessor computer 40 Calibration function stored, by means of which measured strain gauge resistances uniquely the sizes of in the torque wrench 50 initiated torques can be assigned.

Below is the operation of the second embodiment of the invention described, with only the differences to the functioning of the in Figure 1 shown torque wrench 10 is received. After this Transmission of the identification signal by the as a signal output device functioning radio transmitter 38 to the external signal receiving device and the The external control device sends further processing in the external control device Control signals to the torque wrench 50 when testing is released. These control signals are used by the control signal receiving device serving radio receiver 68 receive and include a Tripping torque setting signal, which is used to set the reference torque serves. The release signal to the torque wrench is also preferred transfer.

The received control signals are sent to the microprocessor computer 40 as electrical signals forwarded. After the user receives the release signal has perceived, for example, by lighting up a not shown LED on the outside of the housing body 12, it sets the torque wrench 50 to the screw connection of the workpiece to be tested and starts by checking the tightening torque. This in the key initiated torque leads to a bending of the torque rod 22, which is detected by the strain gauge bridge 66. As described above, the microprocessor can unequivocally detect such a bend Assign torque.

The torque signal obtained in this way is combined with the reference torque signal compared that from the previously received trip torque unit signal was obtained. If the torque signal is equal to or greater than this reference torque signal, the torque rod 22 is triggered by the locking device 64 by outputting an unlocking signal, whereupon the torque wrench 50 "kinks". For this purpose, the microprocessor computer 40 controls the energization of the solenoid 58 such that the locking bolt 56 is retracted longitudinally in the direction of the spring 60 to release from the locking recess 54. So that can pivot the torque rod 22 about the pivot pin 26 until the locking body 52 strikes against the inner wall of the housing body 12. The User hears this "kinking" of the torque wrench 50 noticeably true.

The torque wrench 50 becomes after the locking device is triggered 64 further rotated to further increase the tightening torque, see above this undesirable increase can be caused by the strain gauge bridge 66 in Connection with the microprocessor computer 40 can be determined. Do that measured torque the amount of a second reference torque, the microprocessor computer generates which is greater than the first reference torque an error signal.

Upon completion of the torque testing process of each predetermined one The radio transmitter 38 sends a screw connection from the microprocessor computer 40 screw control signal generated to the external signal receiving device. The screw connection control signal contains the measured Value of the tightening torque reached and possibly the error signal if the Torque test was not successfully completed. The external control device saves the screw connection control signal and evaluates it and initiates rework accordingly or issues an enable signal from Screwing process.

Instead of the locking device 64 described with reference to FIG. 2, other facilities are also used. In particular, it is possible provided that the torque wrench is not used can, the rear end of the torque rod 22 in the housing body 12th set permanently. The feedback to the user that the reference torque was then achieved by an optical and / or acoustic Display. Furthermore, a vibration sensor can possibly be added to the Handle 14 are integrated, which has a clearly noticeable mechanical signal generated as soon as the reference torque is reached.

Reference list

10th

Torque wrench

12th

Housing body

14

Handle

16

battery

17th

rear end face of the housing body

18th

Battery cover

20th

Torque bar bushing

22

Torque rod

24th

Torque rod recess

25th

Tool holder head

26

Swivel pin

28

rear face of the torque rod

30th

Tripping torque setting

32

feather

34

Spring contact surface of the tripping torque setting

36

Barcode reader

38

Radio transmitter

40

Microprocessor computer

42

Reed switch (torque sensor)

44

Hard magnet

50

Torque wrench (2nd embodiment)

52

Locking body

54

Locking recess

56

Locking bolt

58

Solenoid

60

Return spring

62

Spring system wall

64

Locking device

66

Strain gauge bridge (torque sensor)

Claims (14)

Torque wrench (10; 50) for testing a torque during a screwing process on a workpiece a torque sensor (42; 66) for outputting a torque signal, a workpiece identification device (36) for generating an identification signal which is assigned to the respective workpiece, and a control device (40) which is in signal connection with the torque sensor (42; 66) and the workpiece identification device (36), wherein the control device (40) is designed to compare the torque signal with at least one predetermined or predeterminable reference torque signal and to generate a screw connection control signal based on the identification signal and the torque signal comparison. Torque wrench (10; 50) according to claim 1 with a signal output device (38) for the output of the screw connection control signal and of the identification signal to one of the torque wrenches (10; 50) spatially separately provided signal receiving device with the Control device (40) is in signal connection and is preferably closed a non-contact electromagnetic signal transmission is. Torque wrench (10; 50) according to claim 1 or 2, wherein the torque signal, the reference torque signal and the tightening control signal electrical, magnetic or electromagnetic signals and the control device (40) is a microprocessor computer (40). Torque wrench (10; 50) according to one of the preceding claims, wherein the signal output device (38) is an electromagnetic Transmitter (38) is. Torque wrench (10; 50) according to one of the preceding claims, the workpiece identification device (36) being a code reader, in particular a barcode reader (36). Torque wrench (10) according to one of the preceding claims with buckling rod function, the torque sensor (42) one at a Torque bar (22) attached permanent magnets (44) and a magnetic switch (42), in particular a reed switch (42) or comprises an induction switch and the magnetic switch (42) for detection an offset of the permanent magnet (44) when the Torque rod (22) due to reaching a predetermined one Reference torque is formed relative to the magnetic switch (42). Torque wrench (50) according to any one of claims 1-5, wherein the Torque sensor (66), a strain gauge sensor (66), preferred in the form of a strain gauge bridge (66), which is on one an initiated torque by bending reacting torque rod (22) of the torque wrench (50) is arranged. Torque wrench (50) according to claim 7, wherein on a tool holder (25) of the torque wrench (50) opposite End of the torque rod (22), a locking device (64) is arranged, unlocks the torque rod (22) when it receives an unlocking signal from the control device (40). A torque wrench (50) according to claim 8, wherein the locking device (64) a ferromagnetic enclosed by a magnetic coil (58) Locking bolt (56) comprises, which in a locking recess (54) in the torque rod (22) for locking them is insertable, and by applying current to the solenoid (58) can be extracted from this. Torque wrench (10; 50) according to one of the preceding claims, wherein the torque wrench (10; 50) is a control signal receiving device (68) which is in signal connection with the control device (40) stands and for receiving control signals from an external Control device is designed, preferably by non-contact electromagnetic transmission. Method for testing a torque during a screwing process on a workpiece, in particular using a device according to claims 1-10, with the following steps in this order: (a) detecting a workpiece or a workpiece identification, in particular a corresponding code, preferably a bar code; (b) generating an identification signal corresponding to the workpiece; (c) checking the torque of the screw connection of the workpiece and generating a corresponding torque signal; (d) comparing the torque signal with a predetermined or predeterminable reference torque signal; (e) generating a tightening control signal based on the identification signal and the torque signal comparison. The method of claim 11 with the subsequent step of dispensing the screw connection control signal to a receiving device, preferably through a non-contact electromagnetic transmission. The method of claim 11 or 12, wherein immediately after the step (b) the identification signal is output to a receiving device is, preferably by a non-contact electromagnetic transmission. The method of claims 11-13, wherein the reference torque signal depending on the generated identification signal, possibly after a confirmation by the receiving device.

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