WO2000011359A1

WO2000011359A1 - A variable length shaft assembly

Info

Publication number: WO2000011359A1
Application number: PCT/GB1999/002712
Authority: WO
Inventors: Phillip Henry Garland; Richard John West
Original assignee: Bae Systems Plc
Priority date: 1998-08-25
Filing date: 1999-08-17
Publication date: 2000-03-02
Also published as: GB9818382D0; AU5433799A

Abstract

A variable length shaft assembly for removably interconnecting spaced apart first and second members (1, 2), which assembly includes coaxially alignable first and second shaft parts (3, 4), telescopic means (5) for varying the axial length of at least one of the first and second shaft parts (3, 4) relative to the other to vary the length of the coaxially aligned first and second shaft parts (3, 4) between an extended position (6) corresponding to interconnection with the first and second members (1, 2) and a retracted position (7) corresponding to disconnection from at least one of the said first and second members (1, 2) and pivot means (8) for pivoting at least part of the first and/or second shaft parts (3, 4) out of coaxial alignment with one another in the retracted position (7) to permit removal of the assembly from the members (1, 2) or to afford access to at least one of the members (1, 2).

Description

A VARIABLE LENGTH SHAFT ASSEMBLY

This invention relates to a variable length shaft assembly suitable particularly, but not exclusively, for interconnection of units in spaces to which access is limited

A drive shaft comprising one or more parts is often used to transmit rotary motion between a motor and an actuator or between two actuators Sometimes the arrangement for mounting the motors and actuators, or the environment in which they are located, means that the drive shaft or one of the motors or actuators cannot be installed or removed without first removing at least one of the other motors or actuators This is costly in terms of time and complexity of maintenance procedures

There is therefore a need for a variable length shaft assembly which can be varied in length to engage with or disengage from members such as a motor or actuator so as to afford access thereto

According to the present invention there is provided a variable length shaft assembly for removably interconnecting spaced apart first and second members, which assembly includes coaxially ahgnable first and second shaft parts, telescopic means for varying the axial length of at least one of the first and second shaft parts relative to the other to vary the length of the coaxially aligned first and second shaft parts between an extended position corresponding to interconnection with the first and second members and a retracted position corresponding to disconnection from at least one of the said first and second members and pivot means for pivoting at least part of the first and/or second shaft parts out of coaxial alignment with one another in the retracted position to permit removal of the assembly from the members or to afford access to at least one of the members Preferably said telescopic means includes an axially bored female end portion of the first shaft part and a male end portion of the second shaft part, which male end portion is dimensioned to fit telescopically into a bore in said axially bored female end portion of the first shaft part for axial movement therein by an amount sufficient to vary the shaft assembly length between said extended and retracted positions

Conveniently, ends of the first and second shaft parts remote from said male and female end portions are each formed to operatively engage in a corresponding bore in the respectively associated first and second members

Advantageously the bore in the female end portion of the first shaft part is at least partially internally axially splined for sliding engagement with a correspondingly axially splined region on the male end portion of the second shaft part

Conveniently, the female end portion of the first shaft part is externally threaded over part of its length, and the second shaft part has an axially bored rotatable nut portion radially surrounding and radially spaced from the male end portion, which nut portion bore is internally threaded for engagement with the corresponding external thread on the female end portion of the first shaft part

Advantageously said second shaft part includes a shoulder therearound for abuttal of the nut portion, which shoulder is positioned between the male end portion of the second shaft part and the end of the second shaft part engageable with the first or second member, and with the nut portion and shoulder co-operating releasably to lock said engaged male and female end portions axially with respect to one another

Preferably the assembly includes an external tooth lock washer eatable between said second shaft part shoulder and said nut portion for locking the nut portion to the shoulder in the extended position of the assembly Conveniently the female end portion external thread is a multi-start thread

Advantageously said pivot means includes a first universal joint locatable in the first shaft part between said female end portion and the end of the first shaft part engageable with the first or second member

Preferably said pivot means includes a second universal joint locatable in the second shaft part between said shoulder and the end of the second shaft part engageable with the first or second member

According to a further aspect of the present invention said male end portion of the second shaft part has a removable outer end clamp section for removable clamping engagement therewith and therearound, which clamp section is removably attachable to the axially bored female end portion of the first shaft part via a flange provided around an outermost end of said female end portion, a corresponding flange on an end of the clamp section and removable securing means therebetween, so that the first and second shaft parts can be clamped together in the extended position by the clamp section and put into the retracted position by removal of the clamp section and retraction of the male end portion of the second shaft part into the bore of the female end portion

Conveniently an outermost end of the second shaft part male end portion has a cross-section of at least partially complementary dimensions to that of an interior section of the end clamp section

Advantageously said end clamp section includes two part cylindrical hollow jaw segments hinged together along one mutual longitudinal interface so as to form a cylinder in a closed condition, and bolt means for releasably securing said jaw segments in the closed condition

Preferably each said jaw segment has a plate attached to one part cylindrical end thereof, which plates are co-operatable in the closed condition of the end clamp section so as to form the corresponding clamp section flange which inner face thereof is engageable by and locates an end face of the male end portion when the latter is clamped in the clamp section

Conveniently said pivot means includes a first universal joint and a second universal joint in spaced location in the first shaft part between said female end portion and the end of the first shaft part engageable with the first or second member

Advantageously the assembly includes a removable lock means between at least one of the first and second shaft part ends and their corresponding members, which removable lock means includes a circumferential groove on the at least one of the first and second shaft part ends for alignment with a corresponding internal groove on the corresponding member, and a removable cross pin insertable through the aligned grooves and locked thereto by locking means, so that the at least one of the first and second shaft part ends is prevented from moving with respect to its corresponding member

According to a further aspect of the present invention there is provided a trailing edge flap assembly for an aircraft wing having spaced apart first and second members in the form of bearing housings for motor and/or actuator units, and including a variable length shaft assembly as hereinbefore described, for removably engaging and interconnecting the bearing housings

For a better understanding of the present invention, and to show how the same may be carried into effect reference will now be made, by way of example, to the accompanying drawings, in which

Figure 1 is a partially longitudinally sectioned plan view of a variable length shaft assembly according to a first embodiment of the present invention in an extended position

Figure 2 is a partially longitudinally sectioned plan view of the assembly of Figure 1 in a retracted position, Figure 3 is a plan view of a variable length shaft assembly according to a second embodiment of the present invention in an extended position,

Figure 4 is a plan view of the assembly of Figure 3 in a retracted position,

Figure 5 is an exploded plan view to an enlarged scale of removable lock means according to the embodiments of Figures 1 and 3 of the present invention,

Figure 6 is a sectional end view of part of Figure 5 taken on the line B-B of Figure 5 showing the removable lock means,

Figure 7 is a sectional end view of part of Figure 3 taken on the line A-A in Figure 3, showing an outer end clamp section according to the embodiment of Figure 3,

Figure 8 is a perspective view of the clamp of Figure 7 in a closed position, and

Figure 9 is a perspective view of the clamp of Figure 7 in an open position

A variable length shaft assembly of the present invention as shown in Figures 1 to 7 of the accompanying drawings is intended for use between first and second members or mounting points spaced apart by a fixed distance and is particularly intended for use in the aerospace industry in artefacts such as aircraft For example, in an aircraft wing dπveshaft assembly, broadly comprising a series of drive shafts and members such as motor/actuator units the drive shaft or one of the motors or actuators cannot be installed or removed without first removing at least one of the other motors or actuators A variable length shaft assembly may be used to allow independent retrieval and/or installation of such an assembly motor or actuator as is required

Thus as shown in Figure 1 of the accompanying drawings a variable length shaft assembly according to a first embodiment of the present invention includes spaced apart first and second members 1 2 coaxially a gnable first and second shaft parts 3, 4 and telescopic means 5 for varying the axial length of at least one of the first and second shaft parts 3, 4 relative to the other The length of the coaxially aligned first and second shaft parts 3, 4 is thus varied between an extended position 6 corresponding to interconnection with the first and second members 1 , 2 and a retracted position 7, shown generally in Figure 2, corresponding to disconnection from at least one of the first and second members 1 , 2 As shown in Figure 1 the assembly includes two pivot means 8 such as universal joints for pivoting at least part of the first and/or second shaft parts 3, 4 out of coaxial alignment with one another in the retracted position 7 to permit removal of the assembly from the members 1 ,2 or to afford access to at least one of the members 1 ,2

As further shown in Figure 1 the telescopic means 5 includes an axially bored female end portion 9 of the first shaft part 3 and a male end portion 10 of the second shaft part 4 The male end portion 10 is dimensioned so as to fit telescopically into a bore 9a in the female end portion 9 of the first shaft part 3 and allow axial movement 1 1 therein between the extended position 6 and the retracted position 7 sufficient to disconnect the shaft assembly from the second member 2, as shown in Figure 2 Ends 13, 12 of the first and second shaft parts 3, 4 located remote from the male and female end portions 10, 9 each are formed to engage in corresponding bores 13b 12b in the respectively associated first and second members 1 , 2 as shown in Figure 1

The bore 9a in the female end portion 9 of the first shaft part 3 is at least partially internally axially splined 14a for sliding engagement with a correspondingly axially splined region 14b on the male end portion 10 of the second shaft part 4 as shown in Figure 1

The bore 9a in the female end portion 9 of the first shaft part 3 is externally threaded at 15 over part of its length as shown in Figure 1 and the second shaft part 4 has an axially bored rotatable nut portion 16 radially surrounding and radially spaced from the male end portion 10 The nut portion 16 is internally threaded for engagement with the external thread 15 of the female end portion 9 of the first shaft part 3 which thread 15 is preferably a multi-start thread The second shaft part 4 further includes a shoulder 17 therearound, as shown in Figure 1 , which is positioned between the male^* end portion 10 and the end 12 of the second shaft part 4 engageable with the second member 2 When in the extended position 6, the nut 16 is locked to the second shaft part shoulder 17 by an external tooth lock washer 18a located between the nut portion 16 and shoulder 17 The nut portion 16 and the shoulder 17 thus co-operate releasably to lock the engaged male and female end portions 10, 9 axially with respect to one another A removable lock means 18b may be provided by a circumferential groove 18c on end 13 for alignment with a corresponding internal groove 18f on the first member 1 as shown in Figure 5, such that when a hollow cross pin 18e is inserted through the aligned grooves 18c, 18f and a locking wire 18d is passed therethrough and tightened around member 1 as shown in Figure 6, end 13 is prevented from moving with respect to the first member 1

The pivot means 8 shown in Figure 1 includes a first universal joint 19a, located in the first shaft part 3 between the female end portion 9 and the end 13 engageable with the bore 13b in the first member 1 and a second universal joint 19b, located in the second shaft part 4 between the shoulder 17 and the end 12 engageable with the bore 12b in the second member 2

Figures 3 and 4 of the accompanying drawings show a variable length shaft assembly according to a second embodiment of the present invention generally similar to that of Figures 1 and 2 in which like parts have been given like reference numerals and will not be described further in detail The length of the coaxially aligned first and second shaft parts 3 4 can be varied between an extended position 6 shown in Figure 3 and a retracted position 7 shown in Figure 4, which corresponds to disconnection of end 12 of the second shaft part 4 from the second member 2

In this embodiment the male end portion 10 of the second shaft part 4 has a removable outer end clamp section 20 for removable clamping engagement therewith and therearound, as shown in Figure 3 The clamp section 20 is removably attachable to the axially bored female end portion 9 of the first shaft part 3 via a flange 21 a provided around an outermost end 22 of the female end portion 9, a corresponding clamp section flange 21 b on an end

23 of the clamp section 20 and securing means 21 c therebetween This enables the first and second shaft parts 3, 4 to be clamped together in the extended position 6 by the clamp section 20, and allows retraction of the male end portion 10 of the second shaft part 4 into the bore 9a of the female end portion 9, as shown in Figure 4, into the retracted position 7

As shown in Figure 7 of the accompanying drawings, an outermost end

24 of the male end portion 10 of the second shaft part 4 has a cross-section of at least complementary dimensions to that of an internal section 25 of the clamp section 20, shown in Figures 8 and 9

The end clamp section 20 includes two part cylindrical hollow jaw segments 26a, 26b, as shown in Figures 8 and 9, which are hinged together along one mutual longitudinal interface 27 so as to form a cylinder in a closed condition 28, as shown in Figure 8, and bolt means 29 for releasably securing said jaw segments 26a, 26b together Each jaw segment 26a, 26b has a plate 30a, 30b attached to one part cylindrical end thereof The plates 30a, 30b cooperate in the closed condition 28 so as to form the corresponding clamp section flange 21 b, whose inner face 31 , shown in Figure 9, is engageable by and locates the outermost end 24 of the male end portion 10 when the latter is clamped in the clamp section 20

The pivot means 8 as shown in Figure 3 includes a first universal joint 32a and a second universal joint 32b in spaced location in the first shaft part 3 between the female end portion 9 and the end 13 of the first shaft part 3 engageable with the first member 1

In the first embodiment of the present invention the procedure for varying the shaft assembly length includes releasing the external tooth lock washer 18a from between the second shaft part shoulder 17 and the nut portion 16, thus enabling the nut portion 16 to rotate relative to the externally threaded part 15 of the female end portion 9 As the nut portion 16 is rotated, when viewed end-on from member 2 in the clockwise direction, the nut portion 16 abuts against the second shaft part shoulder 17 As the internal thread of the nut portion 16 engages with the corresponding external multi-start thread 15 of the female end portion 9, and as there is the lock means 18b locking the first shaft end 13 with respect to the first member 1 , the nut portion 16 effects a progressive axial withdrawal of the second shaft part 4 in the direction of arrow 1 1 To counteract a reactive moment induced by the relative rotation between the nut portion 16 and the first shaft part 3, the female end portion 9 is internally splined 14a for engagement with the correspondingly axially splined region 14b on the male end portion 10 of the second shaft part 4 The length of the splined region 14b is at least equal to the distance required to withdraw the end 12 of the second shaft part 4 remote from the male end portion 10, such that ultimately the second shaft end 12 will be successfully removed from the member bore 12b, as shown in Figure 2

In situations where access is required to parts in member 2 alone, the assembly requires no further manipulation, as subsequent pivoting thereof about one or both of the universal joints 19a, 19b provides a clear working space around member 2 In situations where access is required to either the shaft parts and/or parts of member 2 and/or member 1 , end 13 of shaft part 3 can subsequently be removed from its bore 13b upon removal of the locking wire and cross pin 18d, 18e from the aligned grooves 18c, 18f

Re-assembly of the assembly of the first embodiment of the present invention to the extended position 6 is a reverse of the procedure hereinabove described, and for the purposes of this description assumes access has been provided to member 2 alone Thus the nut portion 16 is rotated when viewed end-on from member 2 counter-clockwise, until the second shaft end 12 has fully engaged with bore 12b The nut portion 16 is subsequently locked to the second shaft part shoulder 17 by the external tooth lock washer 18a so as to prevent relative rotation between the first 3 and second 4 shaft parts during operation

With the second embodiment of the present invention the procedure for reducing the shaft assembly length includes removing the securing means 21 c between the flange sections 21 a and 21 b, and removing the bolt means 29 of the end clamp section 20, thereby releasing the jaw segments 26a and 26b The clamp section 20 is then removed from the male end portion 10 of the second shaft part 4, and the second shaft part 4 is retracted out of bore 12b for a distance greater than the thickness of the clamp section flange 21 b, such that the male end portion 10 of the second shaft part 4 is able to engage with the axially bored 9a female end portion 9 of the first shaft part 3 From this position, either the male end portion 10 can be further retracted into the female bore 9a or the female end portion 9 can be withdrawn over the male end portion 10, dependent on which of the members 1 ,2 is to be accessed The axial bore 9a is of length at least equal to the distance required to withdraw either of the ends 13, 12 of the first and second shaft parts 3, 4 respectively, such that either the end 13 of the first shaft part 3 or the end 12 of the second shaft part 4 will be successfully removed from the corresponding bores 13b, 12b

Thus if access is required to parts from one member only, say the second member 2, the male end portion 10 is inserted into the bore 9a until end 12 disengages from its bore 12b The assembly is then free to pivot about universal joint 32a, providing sufficient space for easy access to member 2 Conversely if access is required to parts of member 1 only, the locking wire and cross pin 1 8d 18e are removed from the aligned grooves 18c, 18f and the female end portion 9 of the first shaft part 3 is withdrawn over the male end portion 10 until end 13 disengages from its bore 13b, and the assembly then pivots around universal joint 32b If access is required to parts from members 1 and/or 2 and/or the shaft assembly itself, once one of either ends 12, 13 has been successfully withdrawn from the corresponding bores 12b 1 3b as _ ^ _

hereinabove described, the end remote from the withdrawn end can subsequently be detached from its corresponding bore

Re-assembly of the assembly of the second embodiment of the present invention is a reverse of the above procedure, and for the purposes of this description assumes that access has been provided to member 2 alone Thus the male end portion 10 is withdrawn from within the bore 9a, re-engaging the end 12 of the second shaft part 4 into bore 12b The end clamp section 20 is then positioned between the male end portion 10 of the second shaft part 4 and the female end portion 9 of the first shaft part 3, and the outermost end 24 of the male end portion 10 is engaged with the inner face 31 of plates 30a, 30b as the jaw segments 26a, 26b are closed therearound The jaw segments 26a, 26b of the clamp section 20 are then secured in the closed clamp position 28 by bolt means 29 The flange section 21 b of the clamp section 20, which comprises the plates 30a, 30b when the clamp 20 is in the closed position 28, is thereafter secured to the flange section 21a around the outermost end 22 of the female end portion 9 by securing means 21 c, shown in Figures 3 and 7, which means may be four holes and corresponding bolts The bolt means 29 may be a pinch bolt so as to remove backlash between the end clamp 20 and the male end portion 10 of the second shaft 4 during operation of the assembly

Claims

A variable length shaft assembly for removably interconnecting spaced apart first and second members, which assembly includes coaxially ahgnable first and second shaft parts, telescopic means for varying the axial length of at least one of the first and second shaft parts relative to the other to vary the length of the coaxially aligned first and second shaft parts between an extended position corresponding to interconnection with the first and second members and a retracted position corresponding to disconnection from at least one of the said first and second members, and pivot means for pivoting at least part of the first and/or second shaft parts out of coaxial alignment with one another in the retracted position to permit removal of the assembly from the members or to afford access to at least one of the members

Assembly according to claim 1 , wherein said telescopic means includes an axially bored female end portion of the first shaft part and a male end portion of the second shaft part, which male end portion is dimensioned to fit telescopically into said axially bored female end portion of the first shaft part for axial movement therein by an amount sufficient to vary the shaft assembly length between said extended and retracted positions Assembly according to claim 2, wherein ends of the first and second shaft parts remote from said male and female end portions are each formed to operatively engage in a corresponding bore in the respectively associated first and second members

Assembly according to claim 3, wherein the bore in the female end portion of the first shaft part is at least partially internally axially splined for sliding engagement with a correspondingly axially splined region on the male end portion of the second shaft part

Assembly according to claim 4, wherein the female end portion of the first shaft part is externally threaded over part of its length, and wherein the second shaft part has an axially bored rotatable nut portion radially surrounding and radially spaced from the male end portion, which nut portion bore is internally threaded for engagement with the corresponding external thread on the female end portion of the first shaft part Assembly according to claim 5, wherein said second shaft part includes a shoulder therearound for abuttal of the nut portion, which shoulder is positioned between the male end portion of the second shaft part and the end of the second shaft part engageable with the first or second member, and with the nut portion and shoulder co-operating releasably to lock said engaged male and female end portions axially with respect to one another Assembly according to claim 6, including an external tooth lock washer locatable between said second shaft part shoulder and said nut portion for locking the nut portion to the shoulder in the extended position of the assembly Assembly according to claim 7, wherein the female end portion external thread is a multi-start thread Assembly according to claim 8, wherein said pivot means includes a first universal joint locatable in the first shaft part between said female end portion and the end of the first shaft part engageable with the first or second member Assembly according to claim 9, wherein said pivot means includes a second universal joint locatable in the second shaft part between said shoulder and the end of the second shaft part engageable with the first or second member Assembly according to claim 3, wherein said male end portion of the second shaft part has a removable outer end clamp section for removable clamping engagement therewith and therearound which clamp section is removably attachable to the axially bored female end portion of the first shaft part via a flange provided around an outermost end of said female end portion, a corresponding flange on an end of the clamp section and removable securing means therebetween so that the first and second shaft parts can be clamped together in the extended position by the clamp section and put into the retracted position by removal of the clamp section and retraction of the male end portion of the second shaft pert into the bore of the female end portion Assembly according to claim 1 1 , wherein an outermost end of the second shaft part male end portion has a cross-section of at least partially complementary dimensions to that of an interior section of the end clamp section Assembly according to claim 12, wherein said end clamp section includes two part cylindrical hollow jaw segments hinged together along one mutual longitudinal interface so as to form a cylinder in a closed condition, and bolt means for releasably securing said jaw segments in the closed condition Assembly according to claim 13, wherein each said jaw segment has a plate attached to one part cylindrical end thereof, which plates are co- operatable in the closed condition of the end clamp section so as to form the corresponding clamp section flange, which inner face thereof is engageable by and locates an end face of the male end portion when the latter is clamped in the clamp section Assembly according to claim 14, wherein said pivot means includes a first universal joint and a second universal joint in spaced location in the first shaft part between said female end portion and the end of the first shaft part engageable with the first or second member Assembly according to claim 10 or claim 15, including a removable lock means between at least one of the first and second shaft part ends and their corresponding members, which removable lock means includes a circumferential groove on the at least one of the first and second shaft part ends for alignment with a corresponding internal groove on the corresponding member, and a removable cross pin insertable through the aligned grooves and locked thereto by locking means so that the at least one of the first and second shaft part ends is prevented from moving with respect to its corresponding member A variable length shaft assembly for removably interconnecting spaced apart first and second members, substantially as hereinbefore described and as illustrated in Figures 1 and 2 or Figures 3, 4, 7, 8 and 9 as modified or not by Figures 5 and 6 of the accompanying drawings A trailing edge flap assembly for an aircraft wing having spaced apart first and second members in the form of bearing housings for motor and/or actuator units, and including a variable length shaft assembly according to any one of claims 1 to 17 for removably engaging and interconnecting the bearing housings