Device for selecting a fastener for an aeronautical assembly

Abstract

The invention relates to a device (1) for selecting a rivet length, comprising: - a frame (2); - a length gauge (5) for measuring the length of a hole passing through an assembly of at least two parts and opening onto opposite faces of the assembly for receiving a rivet for holding the two parts together, the gauge comprising a rod (6) mounted so as to slide on the frame and provided with a hooked end (7) projecting from a bearing face (4) of the frame so that the hooked end and the bearing face can bear on the opposite faces of the assembly when the rod extends through the hole; - a transducer (14) mounted on the frame and arranged so as to transform the sliding of the rod into an electrical signal representative of a sliding amplitude; - an electronic circuit (15) connected to the transducer and arranged so as to convert the electrical signal into a value expressed as a rivet-length unit.

Description

[0001]Description Title of the invention: Device for selecting a fastener for an aeronautical assembly. The present invention relates to the field of assembly fasteners and the field of measuring tools. BACKGROUND OF THE INVENTION Assemblies comprising two parts having superimposed portions with through holes for rivets are known. Each rivet comprises a body having an end with a head bearing against a first external surface of the assembly and a free end extending from an opposite face of the assembly and which is plastically deformed to bear against said opposite face in such a way that the superimposed portions are clamped between the head and the plastically deformed end of the rivets. Riveting is a robust and permanent fastening method. Therefore,Riveting appears as a preferred assembly method in aeronautical structures. However, the quality of the rivet's fastening depends on the length of the rivet body, which must be adapted to the length of the hole. The length of the through hole is generally measured using a measuring tool consisting of a ruler that is inserted into the through hole and graduated in rivet length units, so that by reading the graduation corresponding to the hole length, the user directly obtains the length of rivet to be used. Reading conditions (lighting, position, etc.) and the user's physical condition (fatigue, poor eyesight, inattention) can lead to an incorrect reading, the consequences of which can be catastrophic (rivet failure and jeopardizing the integrity of the assembly). Furthermore,There are several types of rivets, and the rivet length to be used depends on the rivet type. Therefore, there is a dedicated measuring tool for each type of rivet. Consequently, there is a risk that the user may make a mistake when choosing the measuring tool. If the user notices an error in the length of one of the installed rivets, they must remove the rivet, resulting in a loss of time and a risk of damage to one or both parts. Removing this rivet can also lead to the presence of an unwanted foreign body (FOD) within the through hole. These errors require a number of part analyses, disruption, or even a production stoppage. Furthermore, purchasing all the specific measuring tools for a particular type of fastener represents a significant cost. OBJECT OF THE INVENTION The invention aims, in particular, to remedy, at least in part, the aforementioned drawbacks. SUMMARY OF THE INVENTION To this end, it is provided,According to the invention, a rivet length selection device comprises: - a frame, - a length gauge consisting of a hole passing through an assembly of at least two parts and opening onto opposite faces of said assembly to receive a rivet for securing the two parts, the gauge having a rod mounted to slide on the frame and having a hooked end extending beyond a bearing face of the frame so that the hooked end and the bearing face can bear against the opposite faces of the assembly when the rod extends into the hole, - a transducer mounted on the frame and arranged to transform the sliding of the rod into an electrical signal representing a sliding amplitude, - an electronic circuit connected to the transducer and arranged to convert the electrical signal into a value expressed in at least one unit of rivet length and to display it on a display. Thus,A new rivet length selection device is advantageously proposed. The length gauge rod is inserted from one face of the assembly into the through hole to hook the opposite face of the assembly by sliding it relative to the frame resting on the first face of the assembly. The transducer measures the amplitude of the displacement and thus the length of the through hole, which the electronic circuit converts into the expected rivet length. However, the rivet length is expressed in a specific unit of length. The electronic circuit therefore converts the length measured by the transducer into a value expressed in at least one rivet length unit, and this value is displayed on a screen. This is much simpler for the user than determining the value on the graduation system of a dedicated measuring tool. Therefore,User reading errors are avoided. Furthermore, the selection device can be configured to replace a wide range of measuring tools. Consequently, the choice of measuring tool can no longer be a source of error for the user. Eliminating these sources of error improves the quality of assemblies and provides peace of mind for the user, saves time, and reduces maintenance and production costs. The use of an electronic circuit can also ensure traceability of the expressed values. Depending on optional features, used individually or in whole or in part in combination: - the electronic circuit includes a table relating hole lengths to values ​​expressed as a plurality of rivet length units corresponding to a plurality of predetermined rivet types; - the device includes a housing mounted on the frame,The housing containing the transducer, at least part of the electronic circuit, and the display, which is arranged to show the value expressed in units of rivet length; - the electronic circuit includes a measuring circuit arranged within the housing and a processing circuit located remotely from the housing, the measuring circuit being connected to the transducer; - the processing circuit is arranged in a computer terminal programmed to communicate with the measuring circuit of the housing via a transmitter connected to the measuring circuit and a receiver connected to the processing circuit; - the electronic circuit includes an integrated processing circuit arranged to provide the value expressed in units of rivet length and connected to the display of the housing.The electronic circuit is entirely housed within the casing; the processing circuit includes a rivet type selection menu and an interface designed to allow a user to make a selection from the menu; the device is incorporated into a caliper comprising at least one set of jaws for measuring an internal diameter; the caliper comprises at least one second set of jaws for measuring an external diameter; each set of jaws comprises a movable jaw fixed in translation to the shaft of the length gauge, so that the transducer serves to measure both diameter and length. Other features and advantages of the invention will become apparent from the following description of particular and non-limiting embodiments of the invention. BRIEF DESCRIPTION OF DRAWINGS Reference will be made to the attached drawings.Among these: [Fig. 1] Figure 1 is a schematic elevation view of a rivet selection device, according to the invention, in use; [Fig. 2] Figure 2 is a perspective view of the selection device illustrated in Figure 1; [Fig. 3] Figure 3 shows a schematic of a housing and a computer terminal of the selection device illustrated in Figure 2; [Fig. 4] Figure 4 is a schematic front view of an alternative embodiment of the selection device according to the invention. DETAILED DESCRIPTION OF THE INVENTION With reference to Figure 1, the invention relates to the assembly of at least one first part P1 and a second part P2 which are joined together. Parts P1 and P2 are drilled with a through hole T opening onto opposite faces F1, F2 of said assembly to receive a rivet for holding the two parts P1 and P2 together. In particular,The invention relates to a rivet-length selection device 1. With reference also to Figure 2, the selection device 1 comprises a frame 2 extending longitudinally along a first axis X. The frame 2 is, here, shaped as a rectangular parallelepiped whose thickness is negligible compared to the other two dimensions. The frame 2 could have any other shape suitable for its function. The frame 2 comprises a first end 3 and a second end 4, opposite the first end 3. The second end 4 has an edge wider than that of the first end 3. The selection device 1 also comprises a gauge of length 5. The gauge of length 5 extends along the first axis X. The gauge of length 5 comprises a rod 6, extended by a hooked end 7, projecting from a first bearing face integral with the frame 2. More precisely,The rod 6 extends outward from the second end 4, forming the first bearing face integral with the frame 2. The hooked end 7 of the gauge includes a face forming a second bearing face 8. The second bearing face 8 forms a right angle with the rod 6. The second bearing face 8 is located opposite the frame 2. More precisely,The second support face 8 is located opposite the second end 4, which forms the first support face integral with the frame 2. The rod 6 is mounted to slide within the frame 2 as needed by the user and includes a lug or slider (not visible in the figures) allowing the user to slide the rod 6 relative to the frame 2. The rod 6 thus extends between a service position in which it is fully extended outwards from the frame 2 and a rest position in which it is fully retracted inwards from the frame 2. The selection device 1 also includes a housing 9. In this case, the housing 9 is fixedly mounted on the frame 2. The housing 9 is shaped like a parallelepiped and extends lengthwise along the first axis X and widthwise along a second axis Y, the second axis Y being perpendicular to the first X. Of course,The housing 9 could have any other shape adapted to its function. The housing 9 includes a first side panel on which is arranged at least one knob 10 which, if necessary, allows the rod 6 to be locked in position relative to the frame 2. The housing 9 includes a second side panel, opposite the first side panel, on which are arranged at least one push button and preferably at least two push buttons. In the present case, the housing 9 includes a first push button 11 and a second push button 12. The housing 9 also includes a display 13 arranged on an upper face of said housing 9, the upper face being perpendicular to the first and second side panels. The display 13 is, for example, a liquid crystal display (LCD). With reference to Figure 3, the housing 9 also includes a transducer 14,arranged inside said housing 9. The transducer 14 is therefore mounted on the frame 2. In this case, the transducer 14 is an active electromechanical transducer. Indeed, the transducer 14 is arranged to transform the sliding of the rod 6 into an electrical signal representing a sliding amplitude. By way of example, the rod 6 may include an optical coding pattern extending over at least part of the length of the rod 6, and the transducer 14 may include an optronic reader capable of reading the part of the optical coding pattern facing it to deduce a position of the rod 6 relative to the frame 2. Alternatively,The rod 6 may include a magnetic pattern extending over at least part of its length, and the transducer 14 may include a magnetic reader capable of detecting the magnetic field of the magnetic pattern facing it to deduce the position of the rod 6 relative to the frame 2. The housing 9 contains an electronic circuit 15. The electronic circuit 15 includes a measurement circuit 16 and a processing circuit 17 integrated into the housing 9. The electronic circuit 15 includes at least one processing component 18 (electronic and / or software), which is, for example, a general-purpose processor, a digital signal processor (DSP), a microcontroller, or a programmable logic circuit such as a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC). The measurement circuit 16 is electrically connected to the transducer 14. Therefore,The measuring circuit 16 receives the electrical signal representing a sliding amplitude and converts it into a value expressed in a specific unit of length. The term "specific" will be defined later. The electronic circuit 15 also includes a power supply system 19 arranged to provide power to all the components of the housing 9 that require it. The power supply system 19 is, for example, a battery. The display 13 is electrically connected to the electronic circuit 15. Furthermore, the first push button 11 is electrically connected to the electronic circuit 15 and allows, by a long press, switching the electronic circuit 15 and the display 13 on or off, and, by a short press, resetting the measuring circuit 16. Switching off the electronic circuit 15 also resets said measuring circuit 16. On the other hand,The second push button 12 is also electrically connected to the electronic circuit 15 and allows a measurement to be acquired. The processing circuit 17 further includes a transmitter 20 for communicating with a receiver 21 arranged in a computer terminal 22. The computer terminal 22 includes a human-machine interface. Moreover, the computer terminal 22 includes at least one processing component (electronic and / or software), not shown, which is, for example, a general-purpose processor, a processor specializing in signal processing (or DSP, for Digital Signal Processor), a microcontroller, or a programmable logic circuit such as an FPGA (for Field Programmable Gate Arrays) or an ASIC (for Application Specific Integrated Circuit). The computer terminal 22 also includes one or more memories (and in particular one or more non-volatile memories), not shown.connected to or integrated into the processing component. At least one of these memories forms a computer-readable storage medium on which is recorded at least one computer program comprising instructions that lead the processing component to execute at least some of the steps of the selection process that will be described below. Communication between the transmitter 20 and the receiver 21 is carried out, for example, via the telecommunications standard known as "Wi-Fi" or "Bluetooth". The operating principle of the invention will now be described. As mentioned previously, the through hole T is intended to receive a rivet for securing the two parts P1 and P2. Since there are several types of rivets,The user must choose both the correct rivet type and the correct rivet length. The user powers on the electronic circuit 15 by pressing the first push button 11. Through the human-machine interface of the computer terminal 22, the user selects the desired rivet type from a rivet type selection menu. The rivet type selection is then transmitted from the receiver 21 to the transmitter 20 of the processing circuit 17, which then selects the rivet length unit corresponding to the selected rivet type. The rivet type could also be selected directly using a third button on the housing 9, and the selected rivet would be displayed on the display 13. The rivet length unit is, as previously described, a specific unit of length. By particular, we mean that the unit of length is a unit of rivet length expressed in dashes,better known by its English term "dash". The "dash" corresponds to an imperial unit in fractions of an inch. Rivet diameters are generally measured in increments of, Rivet diameters and lengths are generally measured in inch increments, expressed as a dash at the end of the rivet identification number. Ideally, the diameter of the chosen rivet should be 4 to 6 thousandths of an inch smaller than the diameter of the through hole T. The rivet diameter is selected in a conventional manner. Referring to Figure 1, the user grasps the selection device 1 and inserts the hooked end 7 of the stem 6 of the length gauge 5 into the through hole T. The user then slides the stem 6 until the bearing face 8 of the hooked end 7 rests against face F2 of the second part P2 to be assembled. The second end 4 of the frame 2, forming the first bearing face, rests against face F1 of the first part P1 to be assembled.The sliding amplitude of the rod 6 is detected by the transducer 14, which generates an electrical signal representing the sliding amplitude. When the user determines that the selection device 1 is correctly pressed against faces F1 and F2, they press the second push button 12 to initiate the measurement. The electrical signal transmitted to the measuring circuit 16 is then converted by the processing component 18 into a length expressed in dashes. To do this, the processing circuit 17 uses a memory containing a table that relates hole lengths to values ​​expressed as a plurality of rivet length units, corresponding to a plurality of predetermined rivet types. The length in dashes is displayed on the display 13 of the housing 9. Simultaneously, the transmitter 20 transmits the rivet length expressed in dashes to the receiver 21, which transmits this value to the memory of the computer terminal 22.This allows the values ​​transmitted by the electronic circuit 15 to be recorded, thus ensuring traceability of the installed fasteners. To take a new measurement, the user briefly presses the first push button 11 to reset the measuring circuit 16. At the end of the measurements, the user presses and holds the first push button 11 to disconnect the power supply to the electronic circuit 15. The rivet length selection process thus comprises the following steps: - insert the hooked end 7 into the hole T and slide the shank 6 relative to the frame 2 so as to bring the hooked end 7 and the bearing face 4 against the opposite faces F2, F1 of the assembly, - read the value expressed in "dash", - insert the corresponding rivet into the hole T. In the variant shown in Figure 4, the selection device 1 is integrated into a caliper 100.It is common to find calipers with a depth gauge: caliper 100 is such a caliper, but in which the depth gauge has been replaced by a length gauge 5. Caliper 100 thus comprises a first set of jaws 101 arranged conventionally for measuring an internal diameter, such as the internal diameter of the through hole T intended to receive the body of a rivet, and a second set of jaws 102 arranged conventionally for measuring an external diameter, such as the external diameter of the body of a rivet. Each set of jaws includes a movable jaw that is integral with the shaft 6 of the length gauge 5, so that the transducer 14 is used to measure external diameter, internal diameter, and length. The frame of caliper 100 supports the housing 9, which, as before, contains the electronic circuit 15.The electronic circuit 15 is arranged to allow selection of the type of measurement to be performed and may include an additional button for making this selection: - external diameter measurement, - internal diameter measurement, - length measurement. The operation of the caliper used to measure the length of a through hole is identical to that described previously. Note that it remains possible to use the length gauge 5 to measure the length of a blind hole by placing the hooked end 7 against the bottom of the blind hole. The operation of the caliper used to measure the external and internal diameters is identical to the conventional operation of a caliper. The electronic circuit 15 can, however, be arranged to automatically convert the measured diameter into a value in rivet diameter units, such as a dash value.It is understood that the caliper then allows the selection of the rivet diameter appropriate for the through hole or the determination of the dimensions of a rivet that is unmarked. The electronic circuit 15 can also be configured to allow conventional use of the caliper by providing a selection menu for displaying measurements in a standard unit of length, such as millimeters. Of course, the invention is not limited to the embodiments described but encompasses any variant falling within the scope of the invention as defined by the claims. In particular, the structure may differ from that described. For example, an elastic return means (not shown) could extend between the frame and the rod to apply a restoring force to the rod so that it returns to its rest position.In particular, although the display here is an LCD screen, it would be possible to implement an E-paper screen or a twisted nematic (TN) screen. While communication between the transmitter and receiver is via a Wi-Fi or Bluetooth module, it would be possible to implement a module compliant with another standard, such as an Ultra Wide Band (UWB) module. The computer terminal described here is, for example, a tablet, a computer, or any other computing device with a human-machine interface.

Claims

CLAIMS 1. A rivet length selection device (1) comprising: - a frame (2), - a length gauge (5) with a through hole (T) in an assembly of at least two parts (P1, P2) and opening onto opposite faces (F1, F2) of said assembly to receive a rivet for retaining the two parts, the length gauge (5) having a rod (6) mounted to slide on the frame (2) and having a hooked end (7) projecting from a bearing face (4) of the frame so that the hooked end (7) and the bearing face (4) can bear against the opposite faces (F1, F2) of the assembly when the rod (6) extends into the hole, - a transducer (14) mounted on the frame and arranged to transform the sliding of the rod into an electrical signal representative of a sliding amplitude. ly,- an electronic circuit (15) connected to the transducer (14) and arranged to convert the electrical signal into a value expressed in at least one rivet length unit and display it on a display (13).

2. Device (1) according to claim 1, wherein the electronic circuit (15) comprises a table relating hole lengths to values ​​expressed in a plurality of rivet length units corresponding to a plurality of predetermined rivet types.

3. Device (1) according to any one of the preceding claims, comprising a housing (9) arranged on the, frame (2), the housing (9) comprising the transducer (14), at least a portion of the electronic circuit (15), and the display (13) which is arranged to display the value expressed in rivet length units.

4. Device (1) according to claim 3, wherein the electronic circuit (15) comprises a measuring circuit (16) arranged in the housing (9) and a processing circuit (17) which is remote from the housing (9), the measuring circuit (16) being connected to the transducer (14).

5. Device (1) according to claim 4, wherein the processing circuit (17) is arranged in a computer terminal (22) programmed to communicate with the measuring circuit (16) of the housing (9) via a transmitter (20) connected to the measuring circuit (16) and a receiver (21) connected to the processing circuit (17). 6.Device (1) according to claim 3, wherein the electronic circuit (15) comprises an integrated processing circuit (17) arranged to provide the value expressed in rivet length units and connected to the display (13) of the housing (9), the electronic circuit (15) being entirely arranged within the housing (9).

7. Device (1) according to any one of claims 4, 5, or 6, wherein the processing circuit (17) comprises a rivet type selection menu and an interface arranged to allow a user to make a selection from the selection menu.

8. Device (1) according to any one of the preceding claims, incorporated into a caliper (100) having at least one first set of jaws (101) for measuring an internal diameter.

9. Device (1) according to claim 8, wherein. The caliper (100) includes at least one second set of jaws (102) for measuring an external diameter.

10. Device according to claim 8 or 9, wherein each set of jaws (101, 102) comprises a movable jaw fixed in translation to the rod (6) of the length gauge (5) so that the transducer (14) serves for measuring diameter and length.

Images