EP4056296A1 - Methode zur überprüfung der qualität der installation einer blindbefestigung - Google Patents

Methode zur überprüfung der qualität der installation einer blindbefestigung Download PDF

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Publication number
EP4056296A1
EP4056296A1 EP22161522.2A EP22161522A EP4056296A1 EP 4056296 A1 EP4056296 A1 EP 4056296A1 EP 22161522 A EP22161522 A EP 22161522A EP 4056296 A1 EP4056296 A1 EP 4056296A1
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EP
European Patent Office
Prior art keywords
point
rod
displacement
contact
sleeve
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EP22161522.2A
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English (en)
French (fr)
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EP4056296B1 (de
Inventor
Dimitri BILLAUD
Benoit Regnard
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LISI Aerospace SAS
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LISI Aerospace SAS
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
    • B21J15/00—Riveting
    • B21J15/10—Riveting machines
    • B21J15/28—Control devices specially adapted to riveting machines not restricted to one of the preceding subgroups
    • B21J15/285—Control devices specially adapted to riveting machines not restricted to one of the preceding subgroups for controlling the rivet upset cycle
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
    • B21J15/00—Riveting
    • B21J15/10—Riveting machines
    • B21J15/28—Control devices specially adapted to riveting machines not restricted to one of the preceding subgroups
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
    • B21J15/00—Riveting
    • B21J15/02—Riveting procedures
    • B21J15/04—Riveting hollow rivets mechanically
    • B21J15/043—Riveting hollow rivets mechanically by pulling a mandrel

Definitions

  • the present invention relates to the installation of blind bindings. More particularly, this invention relates to a blind fastener installation system in which a blind fastener is installed to join multiple sheets together, and the quality of the joint is controlled.
  • the rod has at a first end a shape allowing it to be gripped by a tool to pull it or screw it.
  • the rod has at a second end opposite the first end, a thread engaged with an internal thread of the sleeve, or a head of enlarged diameter relative to the diameter of the rod, engaged with one end of the sleeve.
  • a blind connection is conventionally formed by inserting the rivet or the blind nut into a hole previously formed in the sheets to be assembled.
  • a tool grasps the first end of the rod or of the mandrel, and pulls or screws this rod or this mandrel while maintaining the sleeve or the blind nut against an accessible face of a sheet.
  • the differential force imparted to the sleeve or nut causes plastic deformation of the blind side sleeve or nut, thereby creating a second blind side bearing surface commonly referred to as a "bulb".
  • Rods or chucks generally include a break groove designed to break beyond the application of a certain tensile or torque force. Examples of such rivets or mandrels are described in the document FR3016417 , the document FR1377442 or the document EP1731773A2 .
  • the side of the assembly where the bulb is formed is not accessible so that it is not possible to visually determine if the bulb has actually been formed, if the bulb is of sufficient diameter, if the bulb is well in contact with the blind face, and whether it has a suitable shape.
  • An incorrectly installed blind fixing may not ensure the assembly of the sheets, for example because the bearing surface of the bulb against the blind face is not present. or insufficient, or because the two walls of the bulb are not bearing against each other.
  • the document EP0738551 describes the installation of a pull rivet using a hydraulic gun.
  • the hydraulic power and the displacement of a pull rod of the tool are recorded and processed to plot a displacement/power curve of the piston, and to deduce a speed/displacement curve therefrom. These two curves are used to identify the breaking point of a breaking mandrel of the rivet, and to compare it to an ideal value.
  • the document US 2008/0251268 describes an electric tool for installing a screwed blind rivet, comprising means for analyzing an electric current/time curve in order to detect the breakage of a self-breaking washer and of a threaded part of the fastener, before installing a nut to finalize the assembly.
  • the document EP 0738550 describes a tool and a method for checking a blind pull fastener with frangible pull shank.
  • the tooling comprises a strain gauge which produces a signal representative of the pulling force and an encoder which produces a signal representative of the movement of the pulling rod of the tool.
  • the force/displacement signals are recorded and integrated to determine the total energy used for the pose, and compared to an ideal energy value. Further comparisons are then made.
  • the document WO2018178186A1 describes a method for checking the quality of a blind nut assembly process of two components, in which the force exerted by the tooling and the displacement of the tooling are recorded during the installation of the blind nut.
  • This document teaches to calculate continuously or regularly the derivative of the displacement with respect to the force, and to interrupt the installation process as soon as the value of this derivative exceeds a predetermined value.
  • This predetermined value is defined so as to indicate that the plastic deformation of the sleeve is complete, any subsequent traction unnecessarily causing a significant increase in the force imparted by the tooling to the nut.
  • the document US 4163311 describes a tool for installing a blind rivet under predetermined conditions of force and displacement, comprising means for detecting certain points in real time and interrupting the installation process as soon as the value of these points exceeds a predetermined value.
  • the object of the present invention is to propose a method for checking the installation of a blind binding, making it possible to determine the defective nature of an installation of this blind binding.
  • the process makes it possible to ensure that a bulb has actually been formed, that the two walls of the bulb are in contact with each other and that the total surface of the bulb is in contact with the blind face of the parts to be assembled, and the stiffness in the assembly is greater than an expected value.
  • the invention also relates to a device for implementing the installation quality control method described above, said device comprising processing means able to identify the at least two remarkable points of the at least one signal and to estimating the at least first and second parameters.
  • the figure 1 represents a blind binding 100 marketed by the applicant under the name OPTIBLIND TM (registered trademark).
  • the blind fastener 100 comprises a rod 10 and a sleeve 20 in which the screw is partially housed, and extends longitudinally along an axis X.
  • the rod 10 includes a countersunk head 11, a drive portion 13 extending from the head countersunk, a rupture groove 12 at the junction between said head and the drive portion, as well as a cylindrical barrel 15 placed in the sleeve 20 and comprising a threaded part 152.
  • the sleeve 20 comprises a tubular body 21 surmounted an enlarged collar 22 capable of receiving respectively the cylindrical barrel 15 and the countersunk head 11 of the rod 10.
  • a portion of the sleeve comprises an internal thread 212 capable of engaging with the thread 152 of the rod.
  • the rest of the inner surface 211 of the sleeve is smooth.
  • the drive portion 13 is intended to cooperate with an installation tool, shown schematically in figure 2 and described below. According to the example illustrated, the drive portion 13 comprises a portion 14 able to transmit a screwing torque between the installation tool and the rod 10. The drive portion is also able to transmit to the rod 10 a tensile force exerted by said tool. Breaking groove 12 is designed to break beyond a certain torque applied to rod 10.
  • the figure 2 schematically represents a sectional view of a tool 300 able to install the binding 100.
  • a tool 300 able to install the binding 100.
  • An example of such a tool and its use are for example known from the patent FR3078906B1 of the plaintiff, and will not be described in detail here.
  • the tool 300 comprises a body 310 having a bearing surface 312, a housing 314 for receiving the gripping element 13 of the blind binding 100, and a rotating motor shaft 316 moved by a motor 318, capable of driving the fixing 100 in the axial direction X by means of a ball screw or directly in rotation around the axis X.
  • the tool 300 comprises four strain gauges 320 arranged on the outer surface of the body 310, equidistant from each other, forming a Wheatstone bridge. More or fewer gauges can be arranged on the body.
  • the strain gauges measure the bearing force imparted by the bearing face 312 on the flange 22 of the sleeve during traction, force propagated in the body 310.
  • the tooling does not include a strain gauge but includes a motor current sensor. Regardless of the technology chosen, the signals emitted by the strain gauges or the current sensor are representative of the tensile force F imparted to the fastener 100.
  • the tool further comprises an angle sensor 322, capable of measuring an angular position ⁇ of the motor shaft 316.
  • the picture 3 schematically represents the main installation steps of the binding 100 to assemble a structure 200 comprising a first part 200a and a second part 200b by means of a tool 300.
  • the 3d figure represents the final state of the assembly of the parts 200a and 200b with the binding 100 placed definitively.
  • a first tool can first be used to pull on the drive portion 13 then a second tool can be used to screw the rod 10 in socket 20 and break off the drive portion.
  • a device 400 for controlling the installation of a blind binding can be implemented for blind bindings installed by traction only, not comprising a torsion stage, the drive portion of which breaks beyond a given tensile force.
  • This device can also be implemented for blind fasteners installed by screwing only, not comprising a traction step, the drive portion of which breaks beyond a given torque force.
  • the control device 400 preferably comprises an amplifier 330 adapted to amplify the electrical signals emitted by the strain gauges 320 and the angle sensor 322.
  • the connection between the strain gauges 320, respectively the angle sensor 322, and the amplifier can be wired or wireless.
  • the electrical signals are preferably filtered by filtering means 332 having a bandwidth corresponding to the frequency range of the signals received.
  • Processing means 334 are configured to process the electrical signals, after amplification and filtering. These processing means are in particular configured to calculate parameters during the pulling and tightening step, in particular to identify certain tensile force or torque and displacement values from among the signals received.
  • Comparison means 336 are further configured to compare the parameters with a predefined value or range of values. Depending on the result of this comparison, the deformation of the threaded sleeve is considered to have a correct or defective character.
  • Transmitting means 338 are further configured to transmit an information signal on the correct or defective nature of the installation of the blind fastener 100, after the pulling step, or after the screwing step.
  • This information signal can be an audible signal or a visual signal presented on a screen intended for an operator, on a screen arranged on the tool 300, or even a signal transmitted through a communication protocol, to the attention of a computer equipment or device of an industrial production unit, for example an automated assembly line.
  • the control device 400 can be incorporated in a remote computer, connected or not to the tool 300, or in the tool 300.
  • the principle of the process is based on the identification of particular points of tensile, torque and displacement effort, calculating parameters based on some of these particular points to check whether certain criteria are met, and comparing the results to a predefined condition, generally established by testing on groups of fasteners, for example by diameter, in different configurations, for example in structures of different thicknesses, within the tightening range of the fastener and outside this tightening range, with different tools.
  • the force signals emitted by the strain gauges 320 and the angle measurements ⁇ emitted by the angle sensor 322 are sent to the amplifier 330, each signal being sent according to a frequency specific to the strain gauges and to the angle sensor, preferably identical.
  • the signals are then optionally filtered by the filtering means 332.
  • the processing means 334 process the angle measurements to optionally transform them into displacement X - certain angle measurements can however be processed without being transformed into displacement.
  • the processing means 334 sample the tensile or torque forces.
  • the processing means 334 thus make it possible to process the tensile forces F or of torque C and the angles ⁇ to create a curve of force or torque versus displacement.
  • the figure 5A represents a curve of tensile force/torque versus translational and angular displacement obtained during the installation of a fastener pulled and then screwed.
  • the displacement of the rod 10 and the angle of rotation A of the screw are indicated on the abscissa while the tensile force F is indicated on the ordinate to the left of the figure 5 , and the couple C on the ordinate to the right of the figure 5A .
  • an additional criterion may be to verify that the screwing of the rod into the sleeve takes place without rotation of the sleeve, when the rod is threaded.
  • Another optional criterion may be to check that the head of the rod is in contact with the collar of the socket, when the rod of the blind fastener has an enlarged head, generally countersunk or protruding.
  • a method for checking the installation of a blind binding of the aforementioned type in which the rod 10 is a screw comprising an external thread therefore comprises the estimation of at least one parameter allowing the evaluation of each of the at least two aforementioned criteria, and the comparison with a predefined condition which can be a threshold value (minimum or maximum) or a range of acceptable values. If one of the criteria is not met, then the installation is considered bad.
  • the characteristic points to be identified will be the points among B0, B1, B2 and B3.
  • the characteristic points to be identified will be among the points C0, C1, C2 and C3 of the curve of the figure 5B , the torque/angular displacement curve having the appearance of a traction curve similar to the traction curve of the figure 5A , between points B0 and B3.
  • one or more parameters based on the values of these points can be used to check whether the criterion is met.
  • these parameters a non-exhaustive list of these parameters will be given by way of example. Several parameters can be used depending on the level of detection that is desired. The greater the number of parameters used, the better the detection of incorrect installations.
  • 'X' indicates the absolute displacement of the rod in mm
  • 'A' indicates the angle of rotation of the fastener in degrees
  • 'F' indicates the tensile force in N measured during installation
  • 'C' indicates a torque in N.m measured during installation.
  • a parameter to verify this criterion can be the measurement of the tensile force F1 at the buckling point B1, compared to a range of values which is a function of the force value of the traction setpoint F3.
  • the tensile force F1 at the buckling point B1 is correct when it is between 70% and 95% of the force F3, as indicated by the relation ⁇ 1 ⁇ below.
  • the choice of the range of values depends on the geometry of the sleeve, its material, the hardness in the portion intended to buckle and the tools used. A value outside this range means incorrect buckling, for example because the hardness of the sleeve is lower or higher than an expected hardness.
  • Another parameter can be the value of the slope of the curve portion 504 between the contact point of socket B2 and the set point B3.
  • the slope of this curve can be calculated as the ratio R1 between the difference in traction force (F3 -F2) between the set point B3 and the contact point of the bush B2, and the difference in displacement (X3-X2 ) between the set point B3 and the contact point of socket B2.
  • the ratio R1 can be calculated using the least squares method applied to the curve portion 504.
  • the R1 ratio is representative of the stiffness of the assembly once the bulb is packed on itself and on the blind face of the structure, and the structural elements are pressed between the collar and the bulb of the sleeve. When this ratio is less than a given value, this parameter indicates that the stiffness of the assembly is less than an expected stiffness, which may indicate an umbrella-shaped bulb, or a reversal of the flange 22, which does not allow ensure correct tightening of the assembly.
  • the R1 ratio must for example be greater than 3,500 N/mm, as indicated by the relation ⁇ 2 ⁇ .
  • This threshold value was established statistically on two hundred installations, by distinguishing between correct installations and incorrect installations, and by calculating for each of the curves the value of the ratio R1.
  • Another parameter can be the difference of the displacement X2 at the point of contact of the sleeve B2 and the displacement X1 at the point of buckling B1 compared to a range of displacement of the difference of the displacement X3 at the set point B3 and the displacement X0 at the point start of traction B0.
  • the parameter range can be between 38 and 57%, as indicated by the relation ⁇ 3 ⁇ .
  • the values of the range can be different depending on the tooling used for the installation, for example between 35 and 60% when the installation is carried out by a robot.
  • Another parameter can be the difference in distance between the displacement X2 at the contact point of the sleeve B2 and the displacement X1 at the buckling point B1, as a function of an expected diameter of the bulb.
  • the displacement X1-X2 is representative of the reduction in length of the blind side sleeve, linked to the screw by the meshing threads, and indirectly of the diameter of the bulb formed. Indeed, if the expected bulb is for example equal to 1.5 times the diameter of the hole, then the reduction in theoretical geometric length is equal to twice the radius of the bulb formed, minus the radius of the hole, as indicated by the relation ⁇ 4 ⁇ .
  • this parameter is less than 3.01 mm, it means that the bulb has not reached its optimum diameter, either because the installed fastener has a clamping capacity less than the thickness of the structure, or the socket n may have deformed for structural reasons, for example because the hardness of the socket is higher than expected.
  • Another parameter can be to compare the difference in the angular displacement of the fastener between the point of contact of the screw S2 and the start point of tightening S1 with a range of angular displacement of the fastener, using the measurements of the sensor of angle 322 without processing this measurement by the processing means 334.
  • the angular displacement between S1 and S2 is an alternative to measuring the displacement between the traction start point B0 and the setpoint B3 - also possible, but it is more precise .
  • the angular displacement of the screw corresponds to a displacement in translation of the screw. An angular displacement outside the expected range indicates that the screw has too much or too little travel in relation to the thickness to be tightened, and therefore that the fastener is not suitable for the thickness to be tightened.
  • a parameter for verifying this criterion can be to compare the torque C3 at the breaking point S3 with an expected torque range. If the gripping element failure occurs below the lower end of the range, the gripping element has probably failed by a combination of bending and twisting, for example because the tooling was applied to the attachment other than in a direction normal to the attachment. A consequence may be that the voltage installed in the screw will not be as expected. If the breakage occurs above the upper end of the range, this may indicate a problem in the installation tooling, or indicate that the break groove is not as defined.
  • An example of this parameter is given by the relation ⁇ 6 ⁇ .
  • Another parameter can be to compare the difference in angle of rotation of the fastener between the breaking point S3 and the contact point of the screw S2 with an angle range.
  • the angle difference can be converted to displacement by multiplying the angle of the rotation by the pitch of the screw thread.
  • the head 11 of the screw is normally supported in or on the collar 22 of the sleeve - depending on the shape of the head, countersunk or protruding.
  • the application of an additional torque does not aim to move the screw, which is physically blocked in translation by the sleeve, but aims to install a tension in the screw, until the moment when the constraint becomes greater than the constraint that can support the break groove 12.
  • a displacement above or below a certain level indicates an installation problem or a fixing problem (material, break throat).
  • An example is given by the relation ⁇ 7 ⁇ .
  • Another parameter can be to calculate the slope of the torque/displacement signal between breakpoint S3 and screw contact point S2, and compare it to a range of values.
  • This slope is mainly representative of the elastic deformation of the screw. When the value of this slope is outside the expected range, it may mean that the screw has not deformed enough or has deformed too much in the longitudinal direction X. For example, an insufficiently formed bulb at the end of the traction step may still be deformed by the rotation of the screw, but this will not be stressed and the slope will be less than the lower limit of the range.
  • An example is given by the relation ⁇ 8 ⁇ .
  • Another parameter can be to compare the difference between the torque at the breaking point S3 and the average of the torque between the screwing start point S1 and the screw contact point S2 at an expected force range.
  • This parameter is representative of the friction torques between the screw and the sleeve. Excessive frictional torques can mean that a large part of the torque imparted to the screw is not used to tension the screw, which can result in insufficient tension in the screw. An example is given by the relation ⁇ 9 ⁇ .
  • Another parameter can be to compare the torque C2 at the contact point of the screw S2, or the average torque between the tightening start point S1 and the contact point of the screw S2, with a maximum threshold torque value, or to a range of torque values.
  • a value lower than the lower limit may reveal the absence of a braking device between the screw and the sleeve, which, in operation, may cause the screw to loosen.
  • An example is given by the relation ⁇ 10 ⁇ .
  • these parameters can be: 6.5 nm ⁇ VS S 3 ⁇ 8 nm 70 ° ⁇ HAS fixation S3 ⁇ HAS fixation S 2 ⁇ 240 ° 5 nm / mm ⁇ slope S 3 ⁇ S 2 ⁇ 30 nm / mm 5.8 nm ⁇ VS S 3 ⁇ VS Mean S 1 ; S 2 ⁇ 8 nm 0.1 nm ⁇ VS S 2 ⁇ 2 nm
  • the screw 10 of the OPTIBLIND TM binding has a countersunk or protruding head 11, of larger diameter than the diameter of the shaft 15 which, once installed in or on the collar 22 of the socket, forms the head of the binding.
  • a type of fixing it is necessary to check that the head 11 of the screw is in contact with the flange 22 of the sleeve.
  • the head of the screw is in contact with the collar of the socket if the displacement of the screw on the tightening zone between S1 and S2 is between 64% and 90% of the displacement of the screw between points B0 and B3 during the pulling step, as indicated by the relation ⁇ 11 ⁇ : 64 % X B 3 ⁇ X B 0 ⁇ X S 2 ⁇ X S 1 ⁇ 90 % X B 3 ⁇ X B 0
  • the head of the screw is in contact with the collar of the socket if the displacement of the screw on the clamping area between S1 and S2 is between 46% and 74% of the movement of the screw between points B0 and B3 during the pulling step.
  • the calculated displacements are not real displacements, but approximations.
  • the position of the tightening start point S1 may differ from the actual tightening start point depending on the signal processing and point detection algorithms used. The ranges indicated then correspond to correction ranges for the above uncertainties.
  • Criterion no. 4 Optional - The screw is screwed into the sleeve without rotating the sleeve.
  • the OPTIBLIND TM binding has the particularity of not having any imprint or means of hanging with a tool on the front face of the collar.
  • the rotation of the sleeve is blocked by the resistant friction generated between the contact surfaces of the sleeve 20 and of the structure 200, the screw 11 being moreover kept in tension on the accessible side of the structure. This phenomenon is generally sufficient to block any rotation, except for example if the fixing is installed in a hole with a diameter that is too large, or if the bulb has not reached the sufficient diameter.
  • a rotation can mean that the bulb is not sufficiently pressed against the rear face, or pressed with some local contact faults, which can induce a loss of preload of the structure in operation. Conversely, a low rotation is not necessarily a sign of poor installation, the residual preload in the structure may be sufficient with regard to the need.
  • a first means of detecting a rotation of the sleeve can simply be a visual means, for example a camera displaying one or more marks affixed to the collar of the socket, placed on the accessible side, during or after installation. These marks may be applied to the bushing flange during manufacture.
  • a second possible way is to calculate the derivative of the torque/displacement curve on the break part between points S2 and S3, and to check that it is always positive. Indeed, a negative derivative indicates an unexpected drop in the applied torque, a sign of sleeve rotation. Such a parameter would thus respond to the relation ⁇ 12 ⁇ : dY I dt I ⁇ I S 2 , I ⁇ I S 3 > 0
  • An improved means is to calculate the derivative centered on at least two values between the points S2 and S3, and preferably on at least five values, in order to avoid calculation errors due to the sensitivity of the angle sensor 322 which can locally induce false calculations.
  • the point B0 can be identified when the tensile force exceeds a threshold value, for example 200 N. This value is in fact sufficient to filter the support forces of the tool on the collar of the sleeve.
  • the point B1 can be identified by studying the variation in slope of the effort curve, for example by calculating the derivative of the curve portions 502 and 503, then by calculating the difference between a sliding average on the left over N points and an average sliding to the right over N points, N being equal to 5 for example. Each of these averages generates a time delay whose difference is an image without delay of the rate of variation of the curve. A moving average is then applied to filter out the difference. The point B1 is given at the zero crossing of this curve or by its minimum, if the zero crossing does not exist.
  • the point B2 can be identified by lowering the slope of the curve portion 504 before reaching the set point force, and by intersecting this slope with the movements on the abscissa. From set point B3, the last points of the curve are scanned and the slope of the straight line thus formed is calculated. The minimum of this slope gives the point B2.
  • Point B3 can be identified as being the first overrun of the setpoint force, for example set at 12,400 N for an OPTIBLIND TM binding with a diameter of 8/32".
  • the screw When the blind fastener is installed by screwing only, the screw does not move in translation, only the threaded socket portion moves in the X direction towards the rear face when the bulb is formed.
  • This displacement can be measured indirectly by measuring the angle of rotation imparted to the screw, and by multiplying this angle by the thread pitch of the screw.
  • a screw having a nominal thread of 0.1900-32 according to AS8879 UNJF-3A the thread has a pitch of 0.79 mm.
  • a rotation of the screw of 360° therefore indicates that the tapping of the sleeve has traversed in translation 0.79 mm.
  • the S1 point can be identified by finding the maximum of the difference between the torque curve and a straight line passing through a point S1 Max , corresponding to the greatest displacement of a set of points defined as being less than a minimum torque, and a point S1 Min , corresponding to the smallest displacement of a set of points defined as being greater than a maximum torque.
  • the point S2 can be identified by finding the maximum of the difference between the torque curve and a straight line passing through a point S2 Min corresponding to the smallest displacement of a set of points defined as being less than a minimum torque, and a point S2 Max corresponding to the greatest displacement of a set of points defined as being greater than a maximum torque.
  • Point S3 can be identified as the last torque reached before the break.
  • Table 1 gives a summary of the results for the twelve parameters used in seven examples.
  • a parameter meeting the criterion is noted as "OK”
  • a parameter not meeting the criterion is noted as "NOK”.
  • the method makes it possible to know that the installation is defective as soon as the pulling step is completed.
  • the analysis is performed in real time, it is not necessary to screw the screw into the sleeve. It is more advantageous for a user to remove the screw by means of the gripping element and then to remove the partially deformed sleeve and proceed to a new installation with another fixing.
  • the analysis is performed after installation, it is not necessary to process the signal from the tightening step.
  • a blind fastener 100 with a diameter of 8/32" (6.32 mm) and a minimum clamping capacity of 12.50 mm is installed in a structure having a hole of 6.35 mm and a thickness of 11, 90 mm
  • the figure 6 shows that the sleeve has deformed incompletely, and has the shape of an umbrella, that is to say that only a small annular portion is actually pressed against the rear face, the edges of the bulb being raised.
  • a blind fastener with a diameter of 8/32" (6.32 mm) and a maximum clamping capacity of 11.31 mm is installed in a structure having a hole of 6.35 mm and a thickness of 11.90 mm.
  • the figure 7 is a photograph of the socket formed on the blind face during this installation, showing that the socket has deformed into a bulb of small diameter.
  • the calculated value is lower than the expected value, which represents a defect linked to the choice of a fixing that is too short by with respect to the thickness of the structure to be tightened, having a deformable effective length of sleeve insufficient for this thickness.
  • a blind fastener with a diameter of 8/32" (6.32 mm) and a clamping capacity of 10.91 to 12.90 mm is installed in a structure having a hole of 9/32" (7.14 mm), i.e. larger than the diameter of the binding, and a thickness of 11.90 mm.
  • the figure 8 and 9 are photographs of the socket formed on the blind face during these two installations, showing that the socket has deformed in one umbrella case and in a second barrel case, i.e. the socket s is slightly deformed during traction.
  • an 8/32" (6.32 mm) diameter blind fastener with a clamping capacity of 10.91 mm to 12.90 mm is installed in a structure with an 8/32" (6. 35 mm), a thickness of 12.90 mm and a slope of 10° on the rear face, i.e. greater than the slope recommended for the installation of the 100 binding.
  • figure 10 is a photograph of the socket formed on the blind face during this installation.
  • an 8/32" (6.32 mm) diameter blind fastener with a clamping capacity of 10.91 mm to 12.90 mm is installed in a structure with an 8/32" (6. 35 mm) and a thickness of 12.90 mm, without bringing the flange 22 of the sleeve into contact with the countersink of the structure. It is therefore an installation fault.
  • the figure 11 is a photograph of the sleeve formed on the blind face during this installation, away from the rear face.
  • a characteristic defect of a lack of support of the bulb on the rear face is also indicated by the relation ⁇ 12 ⁇ , showing a rotation of the sleeve during the screwing step, an axial play existing between the ends of the sleeve 20 and the front 210a and rear 220b faces of the structure.
  • an 8/32" (6.32 mm) diameter blind fastener with a clamping capacity of 10.91 mm to 12.90 mm is installed in a structure with an 8/32" (6. 35 mm) and a thickness of 10.91 mm, without docking the head of the sleeve in the countersink of the structure. It is therefore an installation fault.
  • the figure 12 is a photograph of the socket formed on the blind face during this installation, also at a distance from the rear face. During this installation, the head 11 of the screw could not be docked in the collar 22 of the sleeve, without being able to break the gripping element 13.
EP22161522.2A 2021-03-12 2022-03-11 Methode zur überprüfung der qualität der installation einer blindbefestigung Active EP4056296B1 (de)

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FR2102451A FR3120552B1 (fr) 2021-03-12 2021-03-12 Methode pour controler la qualite de l’installation d’une fixation aveugle

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Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1377442A (fr) 1963-09-21 1964-11-06 Saint Chamont Granat Ets Rivet aveugle
US4163311A (en) 1977-02-28 1979-08-07 Sps Technologies, Inc. Tightening system for blind fasteners
EP0738551A2 (de) 1995-04-20 1996-10-23 Emhart Inc. Vorrichtung und Verfahren zur Überprüfung des Setzens von Blindnieten
EP0738550A2 (de) 1995-04-20 1996-10-23 Emhart Inc. Verfahren und Vorrichtung zum Setzen von Blindnieten und dessen Überprüfung
EP0970766A2 (de) 1997-07-21 2000-01-12 Emhart Inc. Verfahren und Vorrichtung zur Formung einer Stanznietverbindung
EP1731773A2 (de) 2005-06-10 2006-12-13 Newfrey LLC Blindnietanordnung
US20080251268A1 (en) 2006-04-12 2008-10-16 Toshihiko Kushida Electric bolt/nut fastener
US7503196B2 (en) 2004-03-24 2009-03-17 Newfrey Llc Rivet monitoring system
FR2999707A1 (fr) * 2012-12-14 2014-06-20 Airbus Operations Sas Procede et dispositif d'installation controlee d'un element de fixation aveugle
FR3016417A1 (fr) 2014-01-14 2015-07-17 Lisi Aerospace Rivet pour fixation aveugle, outil de pose associe et methode de pose d'un tel rivet
WO2018178186A1 (de) 2017-03-30 2018-10-04 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Verfahren zum setzen einer umformtechnisch gefügten verbindung
FR3078906B1 (fr) 2018-03-13 2020-02-14 Lisi Aerospace Outillage de pose d’une fixation aveugle et procede de pose d’une fixation

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1377442A (fr) 1963-09-21 1964-11-06 Saint Chamont Granat Ets Rivet aveugle
US4163311A (en) 1977-02-28 1979-08-07 Sps Technologies, Inc. Tightening system for blind fasteners
EP0738551A2 (de) 1995-04-20 1996-10-23 Emhart Inc. Vorrichtung und Verfahren zur Überprüfung des Setzens von Blindnieten
EP0738550A2 (de) 1995-04-20 1996-10-23 Emhart Inc. Verfahren und Vorrichtung zum Setzen von Blindnieten und dessen Überprüfung
EP0970766A2 (de) 1997-07-21 2000-01-12 Emhart Inc. Verfahren und Vorrichtung zur Formung einer Stanznietverbindung
US7503196B2 (en) 2004-03-24 2009-03-17 Newfrey Llc Rivet monitoring system
EP1731773A2 (de) 2005-06-10 2006-12-13 Newfrey LLC Blindnietanordnung
US20080251268A1 (en) 2006-04-12 2008-10-16 Toshihiko Kushida Electric bolt/nut fastener
FR2999707A1 (fr) * 2012-12-14 2014-06-20 Airbus Operations Sas Procede et dispositif d'installation controlee d'un element de fixation aveugle
FR3016417A1 (fr) 2014-01-14 2015-07-17 Lisi Aerospace Rivet pour fixation aveugle, outil de pose associe et methode de pose d'un tel rivet
WO2018178186A1 (de) 2017-03-30 2018-10-04 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Verfahren zum setzen einer umformtechnisch gefügten verbindung
FR3078906B1 (fr) 2018-03-13 2020-02-14 Lisi Aerospace Outillage de pose d’une fixation aveugle et procede de pose d’une fixation

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FR3120552B1 (fr) 2024-04-12
EP4056296B1 (de) 2024-04-24
US20220288670A1 (en) 2022-09-15
FR3120552A1 (fr) 2022-09-16
US11826816B2 (en) 2023-11-28

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