Device for the extraction of a bush from a housing and associated method

Abstract

This device (1) for the extraction of a bush (3) from a housing (5) comprises a first part (7), a second part (9) and a lifter guide (11), wherein the first part (7) is movable only along a rectilinear movement and configured to grab and extract the bush (3) during said rectilinear movement, the second part (9) being mobile only in rotat ion on itself and resting on the lifter guide (11), said lifter guide (11) being configured to rest on the housing (5) around the bush (3), the first part (7) and the second part (9) being connected so that the rotation of the second part (9) is instantly converted into the rectilinear movement of the first part (7).

Description

[0001] DESCRIPTION

[0002] TITLE : DEVICE FOR THE EXTRACTION OF A BUSH FROM A HOUSING AND ASSOCIATED METHOD

[0003] Technical field

[0004] The present disclosure pertains to mechanical tools used in aircraft maintenance. It focuses on devices that facilitate the removal of components within auxiliary power units. More specifically, the invention concerns tools designed for extracting bushes from the housing of APU generators.

[0005] Prior Art

[0006] Technicians engaged in the maintenance of mechanical assemblies often encounter difficulties when disassembling components that have become seized within their housings due to thermal effects or contamination from operational byproducts. The traditional methods employed for the disengagement of such components frequently involve manual exertion and can result in inconsistent outcomes. These methods may compromise the integrity of the components, pose safety risks to the operator, and arc labor-intensive, leading to operator fatigue when repetitive tasks arc necessary.

[0007] Challenges in the maintenance and repair of auxiliary power unit (APU) AC generators often involve the removal of bushes from the main housing. The removal process can be particularly arduous when dealing with seized bushes, which is a common occurrence. Seizure typically results from the heat induced by brazing processes, such as debrazing the fork, and can be exacerbated by the deterioration of bushes and firings due to residual oil from the unit.

[0008] Current methods for bush removal typically require manual actions that involve hammering a screw tap into the bush followed by a pulling action to extract the bush. This process not only demands significant physical effort but also poses safety risks. The use of tools like screw taps and hammers can lead to slippage, which may cause injury to the user or damage to the component. Furthermore, the manual effort required can lead to fatigue, especially when multiple bushes need removal. The physical strength required for pulling the bush, combined with the potential for tool slippage due to oil residue, results in a process that is both unsafe and inefficient.

[0009] Disclosure of the invention

[0010] The present di sclosure provides a device for a bush extraction designed to address the aforementioned challenges. The device facilitates the removal of bushes in a manner that minimizes the need for physical strength and reduces the risk of tool slippage and associated safety hazards.

[0011] The device for the extraction of a bush from a housing comprises a first part, a second part and a lifter guide, the first part being movable only along a rectilinear movement and configured to grab and extract the bush during said rectilinear movement, the second part being mobile only in rotation on itself and resting on the lifter guide, said lifter guide being configured to rest on the housing around the bush, the first part and the second part being connected so that the rotation of the second part is instantly converted into the rectilinear movement of the first part.

[0012] Thi s approach not only enhances safety by reducing the likelihood of slippage but al so streamlines the removal process, potentially reducing the time required for bush extraction and mitigating user fatigue. In particular, no manual pulling is required since only a rotational movement can be applied to the second part in order to lift the first part and, doing so, extract the bush.

[0013] According to one aspect of the invention, wherein the first part comprises two shells forming an inner case configured to cover the bush to be extracted, the inner case comprising an outgrow th configured to grab a protrusion of the bush between said bush and the housing, the inner case comprising a first tapped hole facing the bush when the bush is covered by the inner case, said first tapped hole being configured to cooperate with a threaded bolt in rotation from the second part in order to lift and extract the bush from the housing. According to a specific aspect, the inner case comprises a first shell comprising the first tapped hole and a second shell, each of the first shell and the second shell comprising complementary slots designed to permit the assembly of said first shell and second shell.

[0014] Advantageously, the second part comprises a threaded bolt and a fixed nut around said threaded bolt, the lifter guide being configured to cover the inner case and to rest on the housing, the lifter guide comprising a second hole facing the first tapped hole when the inner case is covered by the outer case, the fixed nut being configured to abut against the lifter guide when the threaded bolt is inserted through the second hole and the first tapped hole.

[0015] In one embodiment, the lifter guide comprises an inspection window through which an operator can control the movement of the inner case positioned in the lifter guide.

[0016] The invention also provides a method for the extraction of a bush from a housing with a device as previously defined, wherein the method comprises the following steps:

[0017] - Placing the two shells of the inner case around the bush in order to cover said bush with the inner case and to place the outgrowth of said inner case between the protrusion of the bush and the housing;

[0018] - Positioning the lifter guide over the inner case so that the second hole, the first tapped hole and the bush are aligned;

[0019] - Inserting the threaded bolt in the second hole and in the first tapped hole until the fixed nut is abutting against the lifter guide; and

[0020] - Turning clockwise the threaded bolt so that the inner case is lifted by following a rectilinear movement and extracts the bush from the housing.

[0021] In one other embodiment of the invention, the first part comprises a sharp bar, a pin and a hollow threaded bolt, the hollow threaded bolt comprising a head configured to be inserted in the lifter guide and to face the bush, the hollow threaded bolt being movable between an abutting position against an internal protrusion of the lifter guide and an extraction position, the sharp bar being configured to be hammered through the hollow threaded bolt in the bush in order to grab said bush, and to be secured to the hollow threaded bolt by the insertion of the pin through transversal holes performed in the sharp bar and in the hollow threaded bolt.

[0022] Advantageously, the sharp bar is notched or threaded, the sharp bar being preferably a sharp and threaded screw tap.

[0023] According to an aspect of the invention, the second part compri ses a nut screwed around the hollow threaded bolt and abutting against a surface of the lifter guide, the rotation of the nut implying the rectilinear movement of the hollow threaded bolt and the extraction of the bush from the housing when the sharp bar is hammered in said bush.

[0024] The invention also provides another method for the extraction of a bush from a housing with a device as previously defined, wherein the method comprises the following steps:

[0025] - Placing the lifter guide around the bush in order to cover said bush;

[0026] - Positioning the head of the hollow threaded bolt in the lifter guide against the internal protrusion;

[0027] - Screwing the nut around the hollow threaded bolt until the nut abuts against the surface of the lifter guide;

[0028] - Hammering the sharp bar in the bush through the hollow threaded bolt

[0029] - Securing the sharp bar and the hollow threaded bolt by inserting the pin in transversal holes performed in the sharp bar and in the hollow threaded bolt; and

[0030] - Turning clockwise the nut so that the first part is lifted by following a rectilinear movement and extracts the bush from the housing.

[0031] Brief description of the drawings

[0032] Other advantages and features of the invention will appear from the detailed description of two embodiments of the invention, which are non-limiting examples, illustrated in the appended drawings of which: [Fig 1 ] is a schematized sectional view of a first embodiment of a device according to the invention for extracting a bush from a housing;

[0033] [Fig 2J is a schematized sectional view of a first embodiment of a device according to figure 1 during the extraction of a bush from a housing;

[0034] [Fig 3] is a schematized view of a particular embodiment of an inner case of the device according to figure 1 ;

[0035] [Fig 4] is a schematized view of the steps of a method for the extraction of a bush from a housing using the first embodiment of the device according to figure 1 ;

[0036] [Fig 5] is a schematized sectional view of a second embodiment of a device according to the invention for extracting a bush from a housing;

[0037] [Fig 6] is a schematized sectional view of a second embodiment of a device according to figure 5 during the extraction of a bush from a housing; and

[0038] [Fig 7] is a schematized view of the steps of a method for the extraction of a bush from a housing using the second embodiment of the device according to figure 5.

[0039] Detailed disclosure of at least one embodiment

[0040] The figure 1 is a schematized sectional view of a first embodiment of a device 1 for extracting a bush 3 from a housing 5.

[0041] The housing is for example a housing of an auxiliary power units of an aircraft. Usually, a rod 6 can be positioned through the bush 3.

[0042] This first embodiment permits to reuse the bush 3 after extraction.

[0043] The device 1 comprises a first part 7 , a second part 9 and a lifter guide 1 1 , preferably all made of metal. The first part 7 comprises an inner case 17 configured to cover the bush 3 to be extracted, preferably without touching said bush 3 except for the outgrowth 19.

[0044] The inner case 17 comprises the outgrowth 19 at the bottom of said inner case 17 destined to also be in contact with the housing 5. The outgrowth 19 is configured to be positioned between a protrusion 21 of the bush 3 and the housing 5 in order to grab and lift said bush 3 when the inner case 17 is lifted along a rectilinear movement.

[0045] Thus, for this first embodiment, the bush 3 needs to comprise a protrusion 21 that can be grabbed, and a space the size of the outgrowth 19 needs to be present between the protrusion 21 and the housing 5. If applicable, this space can be formed with a hammer and a lifter or a chisel.

[0046] In one embodiment, the inner case 17 comprises a first shell 13 and a separate second shell 15 permitting to place the inner case 17 around the bush 3 , the two shells 13 and 15 being assembled to form the inner case 17.

[0047] The inner case 17 also comprises a first tapped hole 23 facing the bush 3 when said bush 3 is covered by the inner case 17.

[0048] The first tapped hole 23 is configured to cooperate with a threaded bolt 25 in rotation from the second part 9 in order to lift and extract the bush 3 from the housing 5.

[0049] Thus, the first part 7 is movable only along a rectilinear movement and configured to grab and extract the bush 3 during said rectilinear movement. The first part 7 and the second part 9 are also connected by the connection formed by the threaded bolt 25 and the first tapped hole 23 so that the rotation of the second part 9 is instantly converted into the rectilinear movement of the first part 7.

[0050] The lifter guide 1 1 is configured to cover the inner case 17, preferably without touching it, and to rest on the housing 5 around said inner case 17. Each of the inner case 17 and the lifter guide 1 1 have an annular section and thus are in annular contact with the housing 5.

[0051] The lifter guide 1 1 comprises a second hole 27 facing the first tapped hole 23 when the inner case 17 is covered by the lifter guide 1 1 . The second part 9 comprises more precisely the threaded bolt 25 and a fixed nut 29 around said threaded bolt 25, preferably a threaded hex shape bolt 25. The fixed nut 29 can’ t move along the threaded bolt 25 and is configured to abut against the lifter guide 1 1 when the threaded bolt 25 is inserted through the second hole 27 and the first tapped hole 23.

[0052] Thus, the second part 9 i s mobile only in rotation on itself and rests on the lifter guide 1 1 through the fixed nut.

[0053] When the device is placed around the bush 3, a simple rotation applied on the threaded bolt 25, for example with an Allen key or a spanner, can induce the rectilinear movement of the inner case 17 which will lift and extract the bush 3.

[0054] The figure 2 is a schematized sectional view of the first embodiment of the device 1 while the bush 3 is extracted from the housing 5.

[0055] In a particular embodiment, the second hole 27 can be tapped. In this embodiment, the lifter guide 1 1 rotates with the second part 9 when a rotation is applied on the threaded bolt.

[0056] In another embodiment, the second hole 27 is smooth without tapping. In thi s embodiment, the lifter guide 1 1 has no movement during the extraction of the bush 3.

[0057] In a particular embodiment, the lifter guide 1 1 also comprises an inspection window 31 through which an operator can see and control the movement of the inner case 17 positioned in the lifter guide 1 1.

[0058] Also, in the embodiment of the figures 1 and 2, the two shells 13 and 15 are each one the half of the inner case 17, so that each shell is forming half of the first tapped hole 23.

[0059] The figure 3 is a schematized view of another embodiment of the inner case 17. In this embodiment, the inner case 17 comprises a first shell 13 comprising the first tapped hole 23 and a second shell 15 which is complementary to the first shell 13. Each of the first shell 13 and the second shell 15 comprises complementary slots 33 designed to permit the assembly of said first shell 13 and second shell 15. The figure 4 is a schematized view of the steps of a method for the extraction of the bush 3 from the housing 5 using the first embodiment of the device 1.

[0060] Firstly, we carry out a step 35 of placing the two shells 13 and 15 of the inner case 17 around the bush 3 in order to cover said bush 3 with the inner case 1 7 and to place the outgrowth 1 9 of said inner case 17 between the protrusion 21 of the bush 3 and the housing 5.

[0061] Then we carry out a step 37 of positioning the lifter guide 1 1 over the inner case 17 so that the second hole 27 , the first tapped hole 23 and the bush 3 are aligned. The lifter guide 1 1 must be in contact with the housing 5.

[0062] A step 39 of inserting the threaded bolt 25 in the second hole 27 and in the first tapped hole 23 until the fixed nut is abutting against the lifter guide 1 1 is then carried out.

[0063] Finally, an operator carries out a step 41 of turning clockwise the threaded bolt 25 so that the inner case 17 is lifted by following a rectilinear movement and extracts the bush 3 from the housing 5.

[0064] The figure 5 is a schematized sectional view of a second embodiment of a device 1 for extracting a bush 3 from a housing 5.

[0065] The housing 5 i s for example a housing of an auxiliary power units of an aircraft.

[0066] This second embodiment permits to extract the bush 3 when said bush 3 does not comprise a protrusion 21 . In this second embodiment, the bush 3 is not necessarily reusable after extraction.

[0067] The device 1 comprises a first part 7 , a second part 9 and a lifter guide 1 1 , preferably all made of metal.

[0068] As in the first embodiment, the first part 7 is movable only along a rectilinear movement and configured to grab and extract the bush 3 during said rectilinear movement.

[0069] The second part 9 is mobile only in rotation on itself and rests on the lifter guide 1 1.

[0070] The lifter guide 1 1 is configured to rest on the housing 5 around the bush 3 without any movement, whereas the first part 7 and the second part 9 are connected so that the rotation of the second part 9 is instantly converted into the rectilinear movement of the first part 7.

[0071] The first part 7 comprises a sharp bar 43 , a pin 45 and a hollow threaded bolt 47.

[0072] The sharp bar 43 is intended to mean that the extremity of said sharp bar 43 i s thinner than the rest of the sharp bar 43 , as said sharp bar 43 will be introduced in the bush 3.

[0073] Preferably, the sharp bar 43 is notched or threaded in order to grip the bush 3 when said sharp bar 43 is introduced into the bush 3. The sharp bar 43 is preferably a sharp and threaded screw tap.

[0074] The hollow threaded bolt 47 comprises a head 49 configured to be inserted in the lifter guide 1 1 and to face the bush 3. The head 49 may be hexagonal, and the lifter guide 1 1 may have an internal section with a shape complementary to the section of the head 49 of the hollow threaded bolt 47 , in order to block any rotational movement of the hollow threaded bolt 47.

[0075] More particularly, the lifter guide 1 1 comprises an internal protrusion 51 so that the hollow threaded bolt 47 is movable between an abutting position against the internal protrusion 51 of the lifter guide 1 1 and an extraction position. Preferably, the internal protrusion 5 1 i s annular.

[0076] The sharp bar 43 is configured to be hammered in the bush 3 through the hollow threaded bolt 47 and the lifter guide 1 1 , which have both an internal space 53 for the presence of said sharp bar 43 , in order to grab said bush 3.

[0077] The sharp bar 43 is also configured to be secured to the hollow threaded bolt 47 by the insertion of the pin 45 through transversal holes 55 performed in the sharp bar 43 and in the hollow threaded bolt 47.

[0078] The second part 9 comprises a nut 57 screwed around the hollow threaded bolt 47 and abutting against a surface 59 of the lifter guide 1 1. The surface 59 of the lifter guide 1 1 must be positioned sufficiently away from the internal protrusion 51 of the lifter guide 1 1 , for example at a distance equivalent to the longitudinal dimension of the bush 3. The rotation of the nut 57 implies the rectilinear movement of the hollow threaded bolt 47 and the extraction of the bush 3 from the housing 5 when the sharp bar 43 is hammered in said bush 3.

[0079] The figure 6 is a schematized sectional view of the second embodiment of the device 1 while the bush 3 is extracted from the housing 5.

[0080] The figure 7 i s a schemati zed view of the steps of a method for the extraction of the bush 3 from the housing 5 using the second embodiment of the device 1.

[0081] Firstly, we carry out a step 61 of placing the lifter guide 1 1 around the bush 3 in order to cover said bush 3. The lifter guide 1 1 rests on the housing 5 with an annular contact for example. The lifter guide 1 1 also offers a volume 63 above the bush 3 and below the internal protrusion 51 , permitting the extraction of said bush 3.

[0082] Then, we carry out a step 65 of positioning the head 49 of the hollow threaded bolt 47 in the lifter guide 1 1 against the internal protrusion 51.

[0083] Then, we carry out a step 67 of screwing the nut 57 around the hollow threaded bolt 47 until the nut 57 abuts against the surface 59 of the lifter guide 1 1 .

[0084] Then, a step 69 of hammering the sharp bar 43 in the bush 3 through the hollow threaded bolt 47 is carried out. The sharp bar 43 must be firmly gripped to the bush 3.

[0085] Then, we secure during a step 71 the sharp bar 43 and the hollow threaded bolt 47 by inserting the pin 45 in the transversal holes 55 performed in the sharp bar 43 and in the hollow threaded bolt 47.

[0086] Finally, an operator carries out a step 73 of turning clockwise the nut 57, for example with a spanner, so that the first part 7 is lifted by following a rectilinear movement and extracts the bush 3 from the housing.

[0087] In this step 73 , the nut 57 stays in place against the lifter guide 1 1 whereas the head of the hollow threaded bolt 47 is moving away from the internal protrusion 51.

Claims

CLAIMS1. Device (1) for the extraction of a bush (3) from a housing (5) comprising a first part (7), a second part (9) and a lifter guide (11), wherein the first part (7) is movable only along a rectilinear movement and configured to grab and extract the bush (3) during said rectilinear movement, the second part (9) being mobile only in rotation on itself and resting on the lifter guide (11), said lifter guide (11) being configured to rest on the housing (5) around the bush (3), the first part (7) and the second part (9) being connected so that the rotation of the second part (9) is instantly converted into the rectilinear movement of the first part (7).

2. Device (1) according to claim 1, wherein the first part (7) comprises two shells (13 ; 15) forming an inner case (17) configured to cover the bush (3) to be extracted, the inner case (17) comprising an outgrowth (19) configured to grab a protrusion (21) of the bush (3) between said bush (3) and the housing (5), the inner case (17) comprising a first tapped hole (23) facing the bush (3) when the bush (3) is covered by the inner case (17), said first tapped hole (23) being configured to cooperate with a threaded bolt (25) in rotation from the second part (9) in order to lift and extract the bush (3) from the housing (5).

3. Device (1) according to claim 2, wherein the inner case (17) comprises a first shell (13) comprising the first tapped hole (23) and a second shell (15), each of the first shell (13) and the second shell (15) comprising complementary slots (33) designed to permit the assembly of said first shell (13) and second shell (15).

4. Device (1) according to claim 2 or 3, wherein the second part (9) comprises a threaded bolt (25) and a fixed nut (29) around said threaded bolt (25), the lifter guide (11) being configured to cover the inner case (17) and to rest on the housing (5), the lifter guide (11) comprising a second hole (27) facing the first tapped hole (23) when the inner case (17) is covered by the lifter guide (11), the fixed nut (29) being configured to abut against the lifter guide (11) when the threadedbolt (25) is inserted through the second hole (27) and the first tapped hole (23).

5. Device (1) according to claim 4, wherein the lifter guide (11) comprises an inspection window (31) through which an operator can control the movement of the inner case (17) positioned in the lifter guide (11).

6. Method for the extraction of a bush (3) from a housing (5) with a device (1) according to claim 4 or 5, wherein the method comprises the following steps:Placing (step 35) the two shells (13; 15) of the inner case (17) around the bush (3) in order to cover said bush (3) with the inner case (17) and to place the outgrowth (19) of said inner case (17) between the protrusion (21) of the bush (3) and the housing (5);Positioning (step 37) the lifter guide (11) over the inner case (17) so that the second hole (27), the first tapped hole (23) and the bush (3) are aligned;Inserting (step 39) the threaded bolt (25) in the second hole (27) and in the first tapped hole (23) until the fixed nut (29) is abutting against the lifter guide (11); andTurning (step 41) clockwise the threaded bolt (25) so that the inner case (17) is lifted by following a rectilinear movement and extracts the bush (3) from the housing (5).

7. Device (1) according to claim 1, wherein the first part (7) comprises a sharp bar (43), a pin (45) and a hollow threaded bolt (47), the hollow threaded bolt (47) comprising a head (49) configured to be inserted in the lifter guide (11) and to face the bush (3), the hollow threaded bolt (47) being movable between an abutting position against an internal protrusion (51) of the lifter guide (11) and an extraction position, the sharp bar (43) being configured to be hammered through the hollow threaded bolt (47) in the bush (3) in order to grab said bush (3), and to be secured to the hollow threaded bolt (47) by the insertion of the pin (45) through transversal holes (55) performed in the sharp bar (43) and in the hollow threaded bolt (47).

8. Device ( 1 ) according to claim 7, wherein the sharp bar (43) is notched or threaded, the sharp bar (43) being preferably a sharp and threaded screw tap.

9. Device (1 ) according to claim 7 or 8 , wherein the second part (9) comprises a nut (57) screwed around the hollow threaded bolt (47) and abutting against a surface (59) of the lifter guide (1 1 ), the rotation of the nut (57) implying the rectilinear movement of the hollow threaded bolt (47) and the extraction of the bush (3) from the housing (5) when the sharp bar (43) i s hammered in said bush (3 ).

10. Method for the extraction of a bush (3 ) from a housing (5 ) with a device ( 1 ) according to claim 9, wherein the method comprises the following steps:Placing (step 61 ) the lifter guide ( 1 1 ) around the bush (3) in order to cover said bush (3);Positioning (step 65) the head (49) of the hollow threaded bolt (47) in the lifter guide ( 1 1 ) against the internal protrusion (51 );Screwing (step 67) the nut (57) around the hollow threaded bolt 47) until the nut (57) abuts against the surface (59) of the lifter guide ( 1 1) ;- Hammering (step 69) the sharp bar (43) in the bush (3) through the hollow threaded bolt (47) ;Securing (step 71 ) the sharp bar (43) and the hollow threaded bolt (47) by inserting the pin (45) in transversal holes (55 ) performed in the sharp bar (43) and in the hollow threaded bolt (47); andTurning (step 73) clockwise the nut (57) so that the first part (7) is lifted by following a rectilinear movement and extracts the bush (3) from the housing (5).

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