Torque device for tightening / loosening a nut in a restricted access location and Method of using such a torque device

Abstract

The invention relates to a torque device (40) for tightening / loosening a nut in a restricted access location and a method of using such a device.This device comprises a first part (44) extending in a first direction (X) provided with a sleeve (50) of a shape adapted to the profile of the nut, a second part (46) integral with the first part and extending in a second direction (Y) with an angle of between 60° and 95° relative to the first direction, a third part (48) connected to the second part and extending in a third direction (Z) with an angle of between 60° and 95° relative to the second direction, and a triggering means (62) arranged at the junction between the second and third parts and configured so that the second and third parts are movable relative to each other between a rest position and a travel position when a torque greater than or equal to the predetermined value is exerted by the sleeve on the nut. Figure 6.

Description

Title of the invention: Torque device for tightening / loosening a nut in a restricted access location and Method for using such a torque device Technical field

[0001] The present application relates to a dynamometric device intended for tightening / loosening a nut, in particular used in the aeronautical field, in a confined space, as well as to a method of using such a dynamometric device, and in particular a method of tightening a nut by means of said dynamometric device. STATE OF THE PRIOR ART

[0002] As is known, some aircraft are equipped with one or more additional fuel tanks. An additional fuel tank is generally arranged under the floor of the aircraft cabin, and a junction between this fuel tank and a fuel distribution pipe from this fuel tank is accessible through a hatch in the floor of the aircraft cabin.

[0003] [Fig. 1] schematically represents such an aircraft cabin floor 10 in which a hatch 12 is arranged for access to an additional fuel tank 14.

[0004] The additional fuel tank 14 is fluidically connected to at least one engine 16 of the aircraft by at least one fuel circulation pipe 18. A portion of this pipe 18 is accessible through the opening of the hatch 12. The additional fuel tank 14 is also fluidically connected to a pressurization pump 20 by at least one air circulation pipe 22. A portion of this pipe 22 is accessible through the opening of the hatch 12. In operation, in order to supply the engine 16, the pump 20 has the function of pressurizing the fuel in the additional fuel tank 14, by sending an air flow FA into said additional fuel tank 14 by means of the pipe 22, and consequently, the additional fuel tank 14 sends a fuel flow Fc into the engine 16 by means of the pipe 18.

[0005] [Fig. 2] represents an enlarged view of the hatch 12 of [Fig. 1], and Figures 3 and 4 represent views of the interior of the hatch 12. Each pipe 18, 22 fluidly connected to the additional fuel tank 14 comprises a plate 30 at one of its ends, which is fixed to a wall 24 delimiting a part of the additional fuel tank 14 by means of screws 26 and nuts 28. Between the two pipes 18, 22, at least one housing 32 is arranged, which can contain means for managing operating parameters of the additional fuel tank 14. Below said housing 32 and said pipes 18, 22 is arranged a recovery panel 34 for possible leaks of liquid coming from the pipes 18, 22, or from other elements arranged in the hatch 12.

[0006] For information purposes, the dimensions L12, 112, H12 of such a hatch 12 are generally between 15cm and 25cm for the width L12 of the hatch 12, between 50cm and 70cm for the length 112 of the hatch 12, and between 30cm and 40cm for the useful height H12 of the hatch 12 (between the opening of the hatch 12 and the recovery panel 34).

[0007] The distance DI between a pipe 18, 22 and the housing 32 is generally less than 5 cm, and the distance D2 between a pipe 18, 22 and the recovery panel 34 is generally less than 10 cm.

[0008] In order to correctly fix the pipes 18, 22 to the wall 34 of the additional fuel tank 14, and in particular the plate 30 of said pipes 18, 22, each nut 28 must be correctly (with the correct torque) tightened on a screw 26. In order to tighten said nuts 28 with a correct tightening torque on each screw 26, a tightening tool must be used.

[0009] However, as shown in Figures 2 to 4, the conditions of access to the interior of the hatch 12, around the pipes 18, 22, to tighten said nuts 28 is very restricted. Indeed, around each pipe 18, 22, the operator in charge of tightening said nuts 28 has a space of approximately 10 cm to pass the tightening tool, position it correctly on the nut 28, and carry out the tightening movement until reaching the correct tightening torque of said nut 28, which may, depending on the amplitude of the tightening required, be complicated, or even not be possible in this confined space.

[0010] Access to these nuts 28 is only possible for an operator in a lying position on the ground, blind (no view of the inside of the hatch 12, and therefore of the nuts 28 to be tightened) and only “by touch”, that is to say by progressing by manual exploration.

[0011] Furthermore, the operator must be permanently physically connected to the tightening tool (for example via a link), in order to prevent said tightening tool from falling, which could create significant delays in production in order to recover this tool between the additional fuel tanks 14. The presence of this link complicates the use of the tightening tool, the link being able to get stuck at different places in the hatch 12 providing access to the additional fuel tank 14.

[0012] Thus, access to said nuts 28 in order to tighten them with the desired tightening torque by equipment currently present on the market is not possible, these tools being bulky and not being able to be used in such a restricted space.

[0013] Furthermore, during an aircraft maintenance operation, it may be necessary to check the tightness of said nuts 28, or disassemble / reassemble the pipes 18, 22, and therefore loosen / tighten said nuts 28. However, during such a maintenance operation, the floor 10 of the cabin is then equipped with a floor covering and seats, which makes access to the interior of the hatch 12 even more difficult.

[0014] It is possible to deviate from the use of a pre-shaped tightening tool to tighten said nuts 28 with the correct predetermined tightening torque, by applying suffix R derogations to each aircraft having one or more additional fuel tanks 14 in the configuration described above and shown in [Fig. 1]. A derogation is a lack of conformity of a part of an aircraft with respect to the initially intended definition of the aircraft. A suffix R derogation corresponds to a permanent derogation, which relates to a non-conformity of the aircraft which results in limitations in the use of said aircraft (either operational or maintenance).

[0015] There is therefore a need for a new tightening tool to ensure correct tightening of the junction between the additional fuel tanks on aircraft, which can be used in a confined environment. Summary of the invention

[0016] The present invention aims to provide a device for tightening / loosening a nut with a correct tightening torque which is compact, and which has a shape and dimensions adapted to the use of said device in a space with restricted access.

[0017] To this end, the invention relates to a dynamometric device intended for tightening / loosening at least one nut, comprising a body comprising: - a first part comprising a sleeve of a shape adapted to the profile of the nut to be tightened / to be tightened, the first part extending in a first direction, - a second part having a first end integral with the first part and a second end, the second part extending in a second direction with an angle of between 60° and 95° relative to the first direction, and - a third part having a first end and a second end connected to the second end of the second part, the third part extending in a third direction at an angle of between 60° and 95° relative to the second direction,

[0018] According to the invention, the body also comprising a triggering means arranged at the junction between the second and third parts, the triggering means comprising a ball bearing comprising an outer ring secured to the third part and an inner ring mounted with a ball joint in the ring external and in which the second end of the second part is arranged, the second and third parts being movable relative to each other, at the triggering means, between a first position, called rest, in which the internal ring is coaxial with the external ring when a torque less than a predetermined value is exerted by the socket on the nut to be tightened / loosened, and a second position, called deflection, in which the internal ring is subjected to deflection relative to the external ring, when a torque greater than or equal to the predetermined value is exerted by the socket on the nut to be tightened / loosened.

[0019] Advantageously, such a dynamometric device can be used in a restricted space. In addition, this device makes it possible to ensure that the nut is tightened with the correct torque, which makes it possible to avoid under-tightening of said nut (and therefore avoiding detachment of the nut following vibrations) or over-tightening of said nut (and therefore weakening the fixing linked to the nut).

[0020] According to another characteristic, the first part extends substantially parallel to the third part.

[0021] According to another characteristic, the first part extends in the first direction over a length of between 2cm and 6cm, the second part extends in the second direction over a length of between 5cm and 12cm, and the third part extends in the third direction over a length of between 10cm and 20cm. These dimensions of the dynamometric device make it possible to guarantee the use of said device in a restricted space, and in particular in the restricted space as described above.

[0022] According to another characteristic, the triggering means comprises a ball bearing comprising an outer ring secured to the third part and an inner ring mounted with a ball joint in the outer ring, the second end of the second part being inserted into the inner ring.

[0023] According to another characteristic, the second part is removable relative to the internal ring.

[0024] According to another characteristic, the spherical bearing comprises rolling elements arranged between the inner ring and the outer ring. According to one configuration, the rolling elements are balls. According to another configuration, the rolling elements are rollers.

[0025] According to another characteristic, the third part comprises a gripping element which extends from the first end of the third part in the third direction over a length of between 40% and 80% of a length of the third part in the third direction.

[0026] According to another characteristic, the gripping element has a dimension in a direction radial to the third direction of between 1 cm and 3 cm.

[0027] The invention also relates to a method for tightening at least one nut by means of a dynamometric device as described above. The method comprises: - a positioning step, during which the socket of the device is positioned on the nut to be tightened, - a tightening step, during which a tightening torque is applied to said nut until the triggering means moves from the first position to the second position, - a tightening stop step, during which the application of a tightening torque to the nut is stopped so that the triggering means returns from the second position to the first position, and - a removal step, during which the device socket is removed from the tightened nut.

[0028] According to another characteristic, the tightening method comprises, before the positioning step, a calibration step, during which the movement of the internal ring of the triggering means relative to the external ring is calibrated as a function of the desired tightening torque on the nut to be tightened. Brief description of the drawings

[0029] Other characteristics and advantages will emerge from the description of the invention which follows, a description given by way of example only, with reference to the appended drawings, among which:

[0030] [Fig-1] is a schematic top view of an aircraft cabin floor including an access hatch to an additional fuel tank, already presented,

[0031] [Fig.2] is a schematic top view of the access hatch to an additional fuel tank of [Fig.l], already presented,

[0032] [Fig.3] is a schematic side view of the interior of the access hatch to an additional fuel tank of [Fig.l], already shown,

[0033] [Fig.4] is a schematic sectional view of the interior of the access hatch to an additional fuel tank of [Fig.l], already shown,

[0034] [Fig.5] is a schematic top view of an aircraft comprising an additional fuel tank,

[0035] [Fig.6] is a schematic perspective view of a dynamometric device for tightening / loosening a nut according to one embodiment of the invention,

[0036] [Fig.7] is a schematic top view of the dynamometric device of [Fig.6]

[0037] [Fig.8] is a schematic side view of the dynamometric device of [Fig.6],

[0038] [Fig.9] is a schematic side view of a triggering means of the device torque wrench for tightening / loosening a nut, in the rest position, according to one embodiment of the invention,

[0039] [Fig. 10] is a schematic side view of the triggering means of the dynamometric device for tightening / loosening a nut, in the travel position, according to one embodiment of the invention,

[0040] [Fig. 11] represents a flowchart of a method of using a torque device for tightening / loosening a nut in a restricted space, according to one embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0041] [Fig. 5] represents an aircraft 1 comprising an additional fuel tank 14 intended to supply at least one engine 16 of said aircraft. The additional fuel tank 14 is arranged under the floor of the aircraft cabin, as represented in [Fig. 1] previously described, and is accessible via an access hatch 12, as represented in FIGS. 2 to 4 previously described.

[0042] In order to tighten / loosen the nuts 28 of the plates 30 of the pipes 18, 22, in the restricted space allocated, a dynamometric device 40 is used by an operator. Such a device 40 is shown in Figures 6 to 8.

[0043] The device 40 comprises a body 42 composed of a first part 44, a second part 46 and a third part 48, the second part 46 being arranged between the first and third parts 44, 48.

[0044] The first part 44 of the device 40 comprises a sleeve 50 whose shape is adapted to the profile of the nut 28 to be tightened / loosened. The first part 44 extends generally in a first direction noted X. In the first direction X, the length L44 of the first part 44 is generally between 2cm and 6cm.

[0045] The second part 46 of the device 40 comprises first and second ends 52, 54, and is integral with the first part 44 of the device 40 at its first end 52. The second part 46 extends generally in a second direction denoted Y, which has an angle of between 60° and 95° relative to the first direction X. According to one configuration, the second part 46 is substantially perpendicular to the first part 44, that is to say that the second direction Y is oriented with an angle of 90° relative to the first direction X. In the second direction Y, the length L46 of the second part 46 is generally between 5cm and 12cm.

[0046] The third part 48 of the device 40 comprises first and second ends 56, 58, and is connected to the second end 54 of the second part 46 of the device 40 at its second end 58. The third part 48 extends generally in a third direction noted Z, which has an angle of between 60° and 95° relative to to the second direction Y. According to one configuration, the third part 48 is substantially perpendicular to the second part 46, that is to say that the third direction Z is oriented with an angle of 90° relative to the second direction Y. According to another configuration, the third part 48 is substantially parallel to the first part 44. By “substantially parallel”, it is understood that the angle between the first direction X and the third direction Z is less than or equal to 5°. According to the third direction Z, the length L48 of the third part 48 is generally between 10cm and 20cm.

[0047] The third part 48 comprises a gripping element 60, for example a handle, which extends from its first end 56 towards its second end 58, over at least 40% of the length L48 of the third part 48. The gripping element 60 extends over a length L60 at most equal to 80% of the length L48 of the third part 48. Advantageously, this gripping element 60 has a minimum length which is sufficient to allow a correct grip by the operator, but also a maximum length which is as short as possible so that when tightening a nut, that is to say during the angular movement transmitted by the operator to the device 40, the gripping element 60 does not come into contact with an element of its environment (which is a restricted space, as described previously with regard to FIGS. 1 to 4).Furthermore, the gripping element 60 has a diameter D60 (dimension in a radial direction to the axis extending in the third direction Z) of between 1 cm and 3 cm. Indeed, the gripping element 60 participates, with the device 40, in the amplitude described by the angular tightening movement of the nut, and the larger the diameter of the handle, the more the angular movement of the device 40 can come into contact with its environment.

[0048] According to one configuration, the third part 48 may also comprise an attachment point 72 of a connecting element 74, such as a tie, which makes it possible to connect the device 40 to the operator, and facilitate the recovery of said device 40 if the operator inadvertently releases it. According to another configuration, the attachment point 72 is optional, the device 40 being more easily handled by an operator than the clamping tools of the prior art, and it is therefore possible to prevent the presence of a connecting element 74 between the device 40 and the operator.

[0049] Of course, the dimensions L44, L46 and L48 mentioned here are given for information purposes and are adapted to the case presented in Figures 1 to 4, but the device 40 could have smaller or larger dimensions depending on the environment in which the device 40 is intended to be used.

[0050] The body 42 of the device 40 also comprises a triggering means 62 arranged at the junction between the second and third parts 46, 48 of the device 40. The triggering means 62 is shown more precisely in FIGS. 9 and 10.

[0051] The triggering means 62 comprises a ball bearing 64 comprising an outer ring 66 secured to the third part 48 of the device 40, as well as an inner ring 68 mounted with a ball joint in the outer ring 66 and in which the second end 54 of the second part 46 of the device 40 is inserted. According to one configuration, the second part 46 of the device 40 is force-fitted into the inner ring 68, and is therefore removable. According to another configuration, the second part 46 of the device 40 is made integral with the inner ring 68. The inner 68 and outer 66 rings are coaxial and centered on an axis corresponding to the third direction Z. Rolling elements 70 are arranged between the inner ring 68 and the outer ring 66, around the central axis of the inner 68 and outer 66 rings corresponding to the third direction Z, in order to allow the ball joint connection.The spherical bearing 64 may be a spherical ball or roller bearing, i.e., the rolling elements 70 may be balls or rollers.

[0052] The second and third parts 46, 48 of the device 40 are therefore movable relative to each other at the triggering means 62. [Fig. 9] represents a first position of the triggering means 62, called the rest position, in which a torque less than a predetermined value is exerted on the second part 46 of the device 40 relative to the third part 48 of the device 40. In this rest position, the inner ring 68 is coaxial with the outer ring 66, and the rolling elements 70 are entirely arranged between the inner 68 and outer 66 rings. [Fig. 10] represents a second position of the triggering means 62, called the clearance position, in which a torque greater than or equal to the predetermined value is exerted on the second part 46 of the device 40 relative to the third part 48 of the device 40.In this clearance position, the inner ring 68 is subjected to clearance relative to the outer ring 66, such that the inner ring 68 is no longer coaxial with the outer ring 66, and a portion of certain rolling elements 70 is arranged outside the space between the inner ring 68 and outer ring 66. The inner ring 68 has a clearance angle of between 5° and 15° relative to its central axis, here an axis oriented in the Z direction.

[0053] The triggering means 62 may be a triggering device with a clutch ball / roller torque limiter.

[0054] The assembly formed by the first and second parts 44, 46 of the device 40 may be removable, in order to be able to adapt the dimensions of the sleeve 50 to the nut 28 to be tightened / loosened. More precisely, the first part 44 comprising the sleeve 50, the first and second parts 44, 46 of the device 40 being integral with each other, and the second part 46 of the device 40 being inserted into the internal ring 68 of the triggering means 62, in order to change the sleeve 50 to adapt the device 40 to other nut dimensions 28 not compatible with the socket 50 initially mounted on the device 40, the first and second parts 44, 46 of the device 40 can be interchanged with other first and second parts of the device 40 whose dimensions of the socket 50 would be more suited to the new nut dimensions. This advantageously makes it possible to reuse the third part 48 of the device 40 for different nut dimensions to be tightened / loosened.

[0055] A method of using the dynamometric device 40 by an operator will now be described. The steps of such a method are shown in [Fig. 11].

[0056] For tightening at least one nut 28 using the device 40, the method comprises, once the operator is in position (for example in the restricted space as described in relation to FIGS. 1 to 4), a step E10 of positioning the sleeve 50 of the device 40 on the nut 28 to be tightened. The method then comprises a step E20 of tightening said nut 28 until the triggering means 62 passes from the first rest position to the second travel position. The shape and dimensions of the device 40 are optimized so that the operator can make the device 40 perform a complete tightening movement until the desired tightening torque is reached. In other words, the method comprises a step of applying a tightening torque to the nut 28 until the torque corresponding to the predetermined value is reached.More precisely, as long as the tightening torque exerted by the operator, via the third part 48 of the device 40, on the socket 50 positioned on the nut 28 to be tightened (via the junction between the second and third parts 46, 48 of the device 40 and the integral connection of the first and second parts 44, 46 of the device 40), remains lower than the predetermined value, the triggering means 62 remains in the first rest position. When the torque exerted by the operator on the socket 50 positioned on the nut 28 to be tightened, via the third part 48 of the device 40, becomes greater than or equal to the predetermined value, the triggering means 62 passes into its second travel position. The passage of the travel means from the first to the second position signifies that the tightening torque of the nut 28 has been reached, and that the operator can stop tightening the nut 28.The predetermined value of the torque is pre-calibrated according to the desired tightening torque on the nut 28 to be tightened. As the socket 50 is positioned on the nut 28 to be tightened, the operator will feel the movement of the assembly composed of the first and second parts 44, 46 of the device 40 relative to the third part 48 of the device 40 which he is holding in his hand. Indeed, when the tightening torque is reached, the inner ring 68 which is fixed to the second part 46 of the device 40 is subjected to a movement relative to the outer ring 68 which is fixed to the third part 48 of the device 40. The method then comprises a step E30 of stopping the tightening of the nut 28. Stopping the tightening by the operator will make it possible to cause a return movement of the de- . trigger 62 from its second trigger position to its first rest position. The method comprises a step E40 of removing the sleeve 50 of the device 40 from the tightened nut 28. This method is then repeated for each nut 28 to be tightened.

[0057] The method may comprise a prior step E01 of calibrating the device 40, so as to calibrate the movement of the triggering means 62 as a function of the desired tightening torque on the nut 28 to be tightened.

[0058] For loosening a nut 28, the device 40 can be recalibrated so that a loosening torque greater than the tightening torque necessary to trigger the movement of the triggering means 62 is applied. In other words, the predetermined value of the loosening torque to be applied to trigger the movement of the triggering means 62 can be greater than the predetermined value of the tightening torque which makes it possible to trigger the movement of the triggering means 62. This advantageously makes it possible to have no movement when loosening a nut, and facilitates the use of the device 40 by the operator, and improves its resistance (the loosening torque being applied to the device 40 with the triggering means in the rest position).

[0059] During an aircraft maintenance operation, the device 40 can be used to control the tightening torque of the nuts 28, and to tighten them if their tightening torque is lower than the predetermined value.

Claims

Claims

1. Dynamometric device (40) for tightening / untightening at least one nut (28), comprising a body (42) comprising: - a first part (44) comprising a sleeve (50) of a shape adapted to the profile of the nut (28) to be tightened / loosened, the first part (44) extending in a first direction (X), - a second part (46) having a first end (52) integral with the first part (44) and a second end (54), the second part (46) extending in a second direction (Y) with an angle of between 60° and 95° relative to the first direction (X), and - a third part (48) having a first end (56) and a second end (58) connected to the second end (54) of the second part (46), the third part (48) extending in a third direction (Z) with an angle between 60° and 95° relative to the second direction (Y),the body (42) also comprising a triggering means (62) being arranged at the junction between the second and third parts (46, 48), the triggering means (62) comprising a spherical bearing (64) comprising an outer ring (66) integral with the third part (48) and an inner ring (68) mounted with a ball joint in the outer ring (66) and in which the second end (54) of the second part (46) is arranged, the second and third parts (46, 48) being movable relative to each other, at the triggering means (62), between a first position, called rest position, in which the inner ring (68) is coaxial with the outer ring (66) when a torque lower than a predetermined value is exerted by the sleeve (50) on the nut (28) to be tightened / loosened, and a second position, called clearance position, in which the inner ring (68) is subjected to clearance relative to the outer ring (66),when a torque greater than or equal to the predetermined value is exerted by the socket (50) on the nut (28) to be tightened / loosened.,

2. A dynamometric device (40) according to the preceding claim, wherein the first portion (44) extends substantially parallel to the third part (48).

3. Dynamometric device (40) according to one of the preceding claims, in which the first part (44) extends in the first direction (X) over a length (L44) of between 2cm and 6cm, the second part (46) extends in the second direction (Y) over a length (L46) of between 5cm and 12cm, and the third part (48) extends in the third direction (Z) over a length (L48) of between 10cm and 20cm.

4. A dynamometric device (40) according to one of the preceding claims, wherein the triggering means (62) comprises a spherical bearing (64) comprising an outer ring (66) integral with the third part (48) and an inner ring (68) mounted with a spherical connection in the outer ring (66), the second end (54) of the second part (46) being inserted into the inner ring (68).

5. Dynamometric device (40) according to the preceding claim, in which the second part (46) is removable relative to the internal ring (68).

6. A torque device according to one of claims 4 or 5, wherein the spherical bearing (64) comprises rolling elements (70) arranged between the inner ring (68) and the outer ring (66), and wherein the rolling elements (70) are balls or rollers.

7. Dynamometric device according to one of the preceding claims, in which the third part (48) comprises a gripping element (60) which extends from the first end (56) of the third part (48) in the third direction (Z) over a length (L60) of between 40% and 80% of a length (L48) of the third part (48) in the third direction (Z).

8. Dynamometric device according to the preceding claim, in which the gripping element (60) has a dimension (D60) in a direction radial to the third direction (Z) of between 1 cm and 3 cm.

9. Method for tightening at least one nut (28) by means of a dynamometric device (40) according to one of the preceding claims, comprising: - a positioning step (E10), during which the sleeve (50) of the device (40) is positioned on the nut (28) to be tightened, - a tightening step (E20), during which a tightening torque is applied to said nut (28) until the triggering means (62) moves from the first position to the second position, - a tightening stopping step (E30), during which the application of a tightening torque to the nut (28) is stopped so that the triggering means (62) moves from the second position to the first position, - a removal step (E40), during which the sleeve (50) of the device (40) is removed from the tightened nut (28).

10. Tightening method according to the preceding claim, comprising, before the positioning step (E10), a calibration step (E01), during which the movement of the internal ring (68) of the triggering means (62) relative to the external ring (66) is calibrated as a function of the desired tightening torque on the nut (28) to be tightened.

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