Gravity-based keying device

Abstract

One aspect of the invention relates to a tool (1) for supporting a turbine shaft (3) comprising a plate (10) provided with a plurality of screw holes (12) and a positioning hole (11) arranged between two screw holes (12), the two screw holes (12) and the positioning hole (11) being arranged on the same first circular arc (110) at a first end (114) of the tool, the circular arc having a centre O positioned on an axis X, a device for fastening the shaft (3) being positioned at a second end (113), characterised in that the first end (114) comprises a gravity-based keying device (5), the keying device (5) comprising a pivot connection, a pendulum and a weight positioned at the end of the pendulum, the pivot connection being arranged radially outside the first circular arc (110) and the weight being arranged opposite the pivot connection and comprising a pin that projects from the plate (10), the pin being movable and having a single position in which it is on the first circular arc (110).

Description

DESCRIPTION TITLE: GRAVITY-BASED ERROR-PROOFING DEVICE TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of turbines and more particularly a tool for assembling them.

[0002] The present invention relates to a tool for holding a turbine shaft, as well as an assembly comprising this tool, the shaft and a disc and a method for mounting the assembly. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] Currently, a tooling is used to hold the turbine shaft in place so that it does not flex under its own weight. To ensure proper operation, the tooling must only be mounted vertically. A keying system already exists to ensure it is mounted in this unique (vertical) position. This keying system is necessary because there are numerous holes distributed regularly and circularly on the turbine disc. This keying system is a counter-form with a positioning pin located on the turbine disc, between two holes. The existing tooling has a positioning hole into which the positioning pin fits.

[0004] But this system is not satisfactory because it can happen that operators mount the tooling next to the positioning block, which reduces the efficiency of the tooling since it is not completely vertical when the error-proofing system with the positioning block is not taken into account by the operator. SUMMARY OF THE INVENTION

[0005] The invention offers a solution to the problems mentioned above, by preventing operators from mounting the tooling in any way other than vertically thanks to a gravity-based error-proofing system.

[0006] The tooling for holding a turbine shaft, according to the invention, comprises: a plate with a plurality of screw holes and a positioning hole disposed between two screw holes among the plurality of screw holes, the two screw holes and the positioning hole being arranged on the same first arc of a circle at a first end of the holding tool, the arc of a circle being centered at O ​​and placed on an axis X, a shaft fixing device at a second end of the holding tool, the holding tool is characterized in that the first end includes a gravity locating device, said gravity locating device comprising a pivot joint, a rocker arm and a mass positioned at the end of the rocker arm, the pivot joint being arranged radially outside the first arc of a circle and the mass being arranged opposite the pivot joint and comprising a pin projecting from the plate, said pin being movable and having a unique position where it is on the first arc of a circle.

[0007] A "gravity-based keying device" is a keying device that allows tooling to be mounted in only one position. This single mounting position relies on the movement of a rocker arm under the influence of gravity. Only the vertical position of the rocker arm allows tooling to be mounted.

[0008] The tooling is designed to be mounted on a disc to hold a shaft in its axis; the shaft includes an axis placed on the X-axis. The disc includes mounting holes allowing this mounting of the tooling.

[0009] Thus, when the tooling according to the invention is in a vertical position, the pin correctly enters one of the mounting holes in the disc because the rocker arm, under the effect of gravity, positions itself vertically. If the operator positions the tooling without inserting a positioning pin into the positioning hole, the tooling not being vertical, the rocker arm will tilt under the effect of gravity and thus dislodge the pin from the first arc of the circle, preventing the tooling from being mounted on the turbine shaft.

[0010] Advantageously, the tooling includes another gravity-operated alignment feature positioned symmetrically with respect to the positioning hole. This keeps the tooling parallel to the turbine and reinforces the vertical mounting.

[0011] Advantageously, the pawn is positioned in a window shaped like a second arc. The pawn's movement is thus limited by the window, which simplifies assembly.

[0012] Advantageously, the tooling includes a captive screw comprising a threaded shank and a head, said captive screw being positioned in one of the screw holes, and the pin is placed on the same face as a threaded shank. The captive screws facilitate the operator's work, and the position of the pin prevents the screw from being tightened if the tooling is not correctly assembled.

[0013] Advantageously, the tool includes two captive screws. With two screws, the tool remains parallel to the disc.

[0014] Advantageously, the gravity-operated keying device is placed between the two screw holes.

[0015] A second object of the invention relates to a mounting assembly comprising a shaft, a disc, and a tool with at least one of the preceding characteristics. It is characterized in that the disc has mounting holes distributed circumferentially along a circle corresponding to that of the first arc and a positioning pin, and in that the pin is movable and has a single position where it lies on the same circle as the mounting holes. The position of the mounting holes on a circle corresponding to the first arc allows the screws to be tightened to mount the tool onto the turbine, and mounting is only possible in one position of the pin, namely the vertical mounting position.

[0016] Advantageously, the pin has a lower hardness than the disc. This prevents wear on the disc. Brass could be chosen, for example.

[0017] Advantageously, the positioning stud is placed between two mounting holes. This makes it easier to identify.

[0018] Advantageously, the positioning stud is positioned on the same circle as the mounting holes.

[0019] A third object of the invention relates to a method of assembling an assembly with at least one of the preceding characteristics, characterized in that it comprises the following steps: positioning the holding tool by inserting the positioning pin into the positioning hole, balancing the balance pin by gravity opposite a mounting hole and inserting the pin into said mounting hole, screwing the screws into the mounting holes.

[0020] Thus, operators are prevented from mounting the tooling in any position other than vertically thanks to the gravity-based alignment system of the holding tooling. Indeed, when the tooling is in a vertical position, the pins correctly enter the screw holes because the rocker arm, under the effect of gravity, positions itself vertically.

[0021] Conversely, if the tooling is incorrectly mounted and / or tilted, gravity will cause the rocker arms to shift the pins, which will then come to rest against the disc walls. This is because the rocker arm's movement alters the relative position of the two pins with respect to the shaft axis and, consequently, with respect to the disc holes. As a result, the pins are no longer aligned with the disc holes, preventing the operator from engaging the captive screws in the disc's threaded holes.

[0022] Advantageously, the process includes a step of fixing the holding tool onto the shaft. Once the tool is correctly positioned, the shaft is centered in the disc.

[0023] Other advantages may also become apparent to the person skilled in the art upon reading the examples below, illustrated by the attached figures, given for illustrative purposes. BRIEF DESCRIPTION OF THE FIGURES

[0024] The figures are presented for illustrative purposes only and are in no way limiting to the invention.

[0025] [Fig. 1] is an axial view of a holding tool according to the state of the art in an incorrect position;

[0026] [Fig. 2] is a detail showing a positioning marker;

[0027] [Fig. 3] is a view showing the positioning pin in a positioning hole;

[0028] [Fig. 4] is an axial view of a holding tool according to the invention in a vertical position;

[0029] [Fig. 5] shows a gravity-based error corrector with a balanced pendulum;

[0030] [Fig. 6] is a cross-section of the holding tooling according to the invention with a pin inserted into one of the mounting holes;

[0031] [Fig. 7] is an axial view of a holding tool according to the invention in an incorrect position;

[0032] [Fig. 8] shows the gravity-operated anti-missing mechanism with the pendulum offset from its equilibrium position;

[0033] [Fig. 9] is a cross-section of the holding tooling according to the invention with a pin locked on a disc. DETAILED DESCRIPTION

[0034] Unless otherwise specified, the same element appearing on different figures has a unique reference.

[0035] Throughout the description we will call the upper part of the figures "top" and the lower part of the figures "bottom", gravity is always directed from top to bottom, i.e. vertically.

[0036] The tooling for holding a shaft 3 of the prior art illustrated in Figure 1 comprises a plate 10 with a positioning hole 11 and two screw holes 12. The positioning hole 11 and the two face holes are located at a first end 114 of the plate 10, on a first arc of a circle 110 centered at O ​​on an axis X, the positioning hole 11 being positioned between the two screw holes 12. The plate 10 extends towards a shaft 3 with an axis located on the axis X. It also includes screws 2 with a threaded shank 20 and a head 21.

[0037] The holding tool 1 also includes a fixing device 16 for the shaft 3 located at a second end 113 of the plate opposite the screws 2. This fixing device 16 for the shaft 3 to the holding tool 1 consists of two parts 160 and 161 each having a semi-circular cutout 162 and 163 intended to receive the shaft 3. A screw and nut system allows the two parts 160 and 161 to be opened and closed to place the shaft 3 in them, and then the two parts 160 and 161 to be tightened to fix the shaft 3 to the holding tool 1.

[0038] The disc 4 includes tapped mounting holes 40 and a positioning stud 41 placed on the same arc of a circle 400 parallel to the first arc of a circle 110 as can be seen in Figure 1. There is only one positioning stud 41 because there is only one correct position.

[0039] In the example shown in Figure 1, the holding tool 1 is not positioned radially vertically on the turbine disc 4 because the positioning hole 11 is not aligned with the positioning pin 41 when the operator incorrectly positioned it. "Radially vertical" refers to a position where the tool is parallel to the disc and oriented vertically along the X-axis. This reduces the tool's effectiveness because, since it is not perfectly vertical, it can prevent the shaft from deflecting under its own weight.

[0040] When the holding tool 1 is vertical and therefore correctly positioned, as can be seen in figure 3, the positioning pin 41 is inserted into the positioning hole 11.

[0041] The holding tool 1 according to the invention, visible in Figure 4, comprises a plate 10 with a positioning hole 11 and two screw holes 12, and includes two gravity-operated locating guides 5. The positioning hole 11 is located on the first arc 110 between the two screw holes 12. The plate 10 extends towards the shaft 3 with axis X. It is possible to have only one gravity-operated locating guide 5.

[0042] The gravity-operated orienting device 5, shown in more detail in Figures 5 and 6, comprises a balance wheel 50, a pivot joint 52, and a mass 51 positioned opposite the pivot joint 52 on the balance wheel 50. The balance wheel 50 is free to rotate about an axis Y parallel to the X axis and corresponding to the axis of the pivot joint 52. The mass 51 is positioned at the free end of the balance wheel 50. The pivot joint 52 is fixed to the plate 10. The mass 51 comprises a pin 510 and a weight 511 arranged on either side of the balance wheel 50. The weight 511 facilitates the movement of the balance wheel so that it is positioned vertically.

[0043] The plate 10 comprises a first face 111 opposite the disc 4 and a second face 112 opposite it on which the head 21 of the screws 2 is positioned. The plate 10 is preferably hollowed out by a recess 14 located in the plate 10 to allow the rocker arm 50 to pivot. The plate 10 includes a window 13 in shape of a second arc of a circle 512 provided to allow passage of the pawl 510. The recess 14 has a section of substantially triangular shape in a plane parallel to the faces of the plate 10 and extends by a hollow 15 until it opens at the level of the first face 111 by the window 13. This hollow 15 is in the shape of the same second arc of a circle and intended to receive the weight 511.

[0044] In the illustrated example, the gravity-operated key 5 is integrated into the plate 10 of the holding tool 1, but it could protrude from the plate 10 (more specifically, from the first face 111 of the plate 10), wholly or partially, without departing from the scope of the present invention. For example, only the pin 510 and the balance 50 protrude, with the weight 511 in the recess 15. It is also possible to have the weight 511 and the pin 510 of the mass 51 on the same side of the balance 50.

[0045] The pin 510 preferably has a length dp extending from the first face 111 of the plate 10. This length is greater than or equal to a length dt of the threaded rod 20 extending from the first face 111 of the plate 10.

[0046] The pin 510 has a central position in the window 13 where it is located on the first arc of the circle 110 and can be inserted into one of the mounting holes 40 as can be seen in figure 6. As soon as it tilts into another position, the pin 510 comes out of the first arc of the circle and can no longer be inserted into one of these mounting holes 40.

[0047] Figures 7 to 9 show that when the retaining tool 1 is incorrectly positioned, i.e., not radially vertical as in Figure 4, the pins 510 tilt due to gravity and are no longer aligned with the mounting holes 40 (see Figure 8). They will then abut against the disc 4 (see Figure 9), leaving the retaining tool 1 and the threaded rod 20 some distance from the disc 4. This prevents the screw 2 from being tightened, thus causing the retaining tool 1 to be mounted in an incorrect position. The screws 2 may be captive screws.

[0048] We will now describe the mounting of the holding tool 1 on the disc 4 in the two cases: when it is correctly mounted vertically and when it is incorrectly mounted.

[0049] When the operator correctly mounts the shaft 3 holding tool 1 onto the disc 4 (vertically), the positioning pin 41 is inserted into the positioning hole 11. Each pin 510 comes to equilibrium in the vertical position and between in one of the mounting holes 40. The user then simply screws the screws 2 into the opposite mounting holes 40. The retaining tool 1 is then correctly positioned and the shaft 3 can be fixed to a second end 113 of the plate 10 opposite the screws 2.

[0050] It is possible to fix the shaft 3 to the holding tool 1 before fixing it to the disc 4 without going out of the scope of the present invention.

[0051] Conversely, if the operator incorrectly positions the shaft 3 holding tool 1 by failing to insert the positioning pin 41 into the positioning hole 11, the holding tool 1 will assume an inclined position, and the pins 510 of the gravity-operated alignment guide 5 will shift to one side of the window 13, also shifting away from the circular arcs 110 and 400, and will no longer be aligned with a mounting hole 40. Because the pins 510 protrude from the plate 10, they will keep the holding tool 1 away from the disc 4 and completely prevent the screw 2 from being tightened if dp > dt (i.e., if the pin 510 protrudes more than the screw 2), or limit its tightening otherwise. The operator will thus easily see that the tool is incorrectly positioned and will be unable to secure it in this way.

Claims

DEMANDS

1. Tooling for holding (1) a turbine shaft (3) comprising: - a plate (10) pierced with a plurality of screw holes (12) and a positioning hole (11) disposed between two screw holes (12) among the plurality of screw holes, the two screw holes (12) and the positioning hole (11) being disposed on the same first arc of a circle (110) at a first end (114) of the holding tool (1), the arc of a circle having center O which is placed on an axis X, - a fixing device (16) for the shaft (3) placed at a second end (113) of the holding tool (1), - characterized in that the first end (114) comprises a gravity-operated keying device (5), said gravity-operated keying device (5) comprising a pivot joint (52), a rocker arm (50) and a mass (51) positioned at the end of the rocker arm (50), the pivot joint (52) being arranged radially outside the first arc of a circle (110) and the mass (51) being arranged opposite the pivot joint (52) and comprising a pin (510) projecting from the plate (10), said pin (510) being movable and having a unique position where it is on the first arc of a circle (110).

2. Holding tool (1) according to claim 1, characterized in that it comprises another gravity-operated keying device (5), arranged symmetrically with respect to the positioning hole (11). [Claims] Holding tool (1) according to any one of the preceding claims, characterized in that the pin (510) is arranged in a window (13) in the shape of a second arc of a circle (512).

4. Holding tool (1) according to any one of the preceding claims, characterized in that it comprises a captive screw (2) comprising a threaded rod (20) and a head (21), said captive screw being disposed in one of the screw holes (12), and in that the pin (510) is placed on the same face (111) as a threaded rod (20). [Claims] Holding tool (1) according to one of the preceding claims, characterized in that the gravity keying device (5) is placed between the two screw holes (12).

6. Mounting assembly comprising a shaft (3), a disc (4) and a holding tool (1) according to any one of the preceding claims, characterized in that the disc (4) comprises mounting holes (40) distributed circumferentially along a circle corresponding to that of the first arc of a circle (110) and a positioning stud (41), and in that the pin (510) is movable and has a unique position where it is on the same circle as the mounting holes (40).

7. Assembly according to the preceding claim, characterized in that the pin (510) has a lower hardness than that of the disc (4).

8. Assembly according to any one of claims 6 or 7, characterized in that the positioning stud (41) is arranged between two mounting holes (40).

9. Assembly according to any one of claims 6 to 8, characterized in that the positioning stud (41) is arranged on the same circle as the mounting holes (40).

10. A method for assembling an assembly according to any one of claims 6 to 9, characterized in that it comprises the following steps: - positioning of the holding tool (1) by inserting the positioning pin (41) into the positioning hole (11), - balancing by gravity of the pin (510) of the balance (50) opposite a mounting hole (40) and insertion of the pin (510) into said mounting hole (40), and - screwing the screws (2) into the mounting holes (40).

11. Assembly method according to the preceding claim, characterized in that it includes a step of fixing the holding tool (1) on the shaft (3).

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