GB1604235A

GB1604235A - Hollow flexible joints

Info

Publication number: GB1604235A
Application number: GB1898177A
Authority: GB
Original assignee: Peress J S
Current assignee: Peress J S
Priority date: 1978-05-02
Filing date: 1978-05-02
Publication date: 1981-12-02

Description

(54) HOLLOW FLEXIBLE JOINTS (71) I, JOSEPH SALIM PERESS, a British subject of 19 Oak Hall Park, Burgess Hill, Sussex RH15 ODH, do hereby declare the invention for which I pray that a Patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a hollow flexible joint for use with apparatus subjected to an internal/external pressure differential and to apparatus incorporating such joints. Thus the joint can be used in conjunction with submersible diving apparatus for example an armoured deep diving suit or for any other purpose such as a pipe line in which such a joint or apparatus is required.

In the Applicant's British Patent No.

400386 a joint for use with diving apparatus is described in which sealing is provided by arranging for one part of the joint to move in a chamber carried on the other part of the joint which is fluid filled. In one embodiment described one part of the joint is in the form of an annular piston and the other part is in the form of a part-spherical annular cylinder, the annular piston carries an annular packing which is tightened by the pressure acquired by the liquid during submergence. When in use angular movement of the piston causes a displacement of the fluid in the cylinder from one side to the other and as this fluid is always under pressure the sealing is maintained.

Another joint employing this principle is shown in the Applicant's British Patent No.

1,332,902 which claims a flexible joint for use with apparatus to be subjected to an internal/ external pressure differential comprising an annular male member movably housed within an annular female member, the male member having an annular part-spherical piston which moves in a closed annular part-spherical cylinder carrying a substantially incompressible sealing fluid in the female member and sealing means carried on the cylinder walls which engage and seal the walls of the annular piston.

It has been found in joints employing this construction that it is difficult to provide angular movement of the parts towards one another, from a straight line position better than about 30 40 , the range of movement being controlled by the operating stroke of the annular pistons in the cylinders.

When Such a joint is used, for example, as an elbow joint in a deep diving suit, it therefore restricts the closing movement of the fore arm towards the upper part of the arm above the elbow and the present invention is intended to provide a hollow flexible joint of this general type which will have a greater range of angular movement away from a straight line position than hitherto.

According to the present invention a hollow flexible joint for use with apparatus subjected to an internal/external pressure differential comprises a first and second flexible assemblies each assembly havine an annular male member movable within an annular female member, the male member having an annular piston which can move angularly in sealing engagement in an annular cylinder carrying a sealing liquid in the female member said annular piston and cylinder having longitudinal axes which can move angularly in relation to each other and said flexible assembly having a central position in which the longitudinal axis of its piston is axially in line with the longitudinal axis of its cylinder the axes of the flexible assemblies being angularly inclined to each other when the flexible assemblies are in their central positions, and the male and female members and the annular connecting means being arranged to provide a continuous passage through them at all angles of the joint.

It will be appreciated that the two male members could be connected to the annular connection means in which case the outer movable members would be the female members carrying the cylinders or the female members could be connected to the annular connection means with the piston carrying male members as the outer movable members, or again one male member and one female member could be connected to the annular connection means.

By combining the two flexible assemblies together with their longitudinal axes inclined to each other it is possible to provide a joint which has angular movement between the outer movable members equal to the combined angular displacement of each of the strokes of the pistons in their cylinders.

Preferably, the angle between the longitudinal axes of the flexible assemblies when in their central positions, and the operating stroke of the annular pistons in them are arranged, so that when both pistons are located in positions in which the angle between the movable outer members is at a maximum the axis of the passage through them is substantially straight.

This arrangement is therefore particularly suitable for an elbow joint in a deep diving suit as the parts can be arranged so that the continuous passage through the parts is substantially straight when the dives arm is straight but it will allow a closing angular movement of the two parts sufficient to enable the elbow joint to be properly employed, for example, if the dimensions of the parts are appropriately arranged and the angle between the axes of the assemblies provided by the annular connection means is 1500 and each piston has an angular stroke movement of 30 then the combined angle of movement from the piston in which the continuous passage is substantially straight to the position in which it is cranked at its maximum angle can be approximately 60 , with the axes of the outer movable members at right angles to each other. Allowances will of course have to be made for the various parts employed and the angle may be slightly less than this but it does therefore allow considerably greater angular movement than that available with known joints.

The longitudinal axes of the assemblies when in their central positions can be inclined to each other as desired and preferably they are at an included angle of between 165 and 135 and convenient constructions can be made between 1600 and 1500.

Similarly the relative angular movement between each angular male member and its associated female member can be between 15 and 50 and is between 20 and 40 .

In one convenient construction the annular connection means between the flexible assemblies may comprise a collar the ends of which are inclined to each other and to which the flexible assemblies are connected.

The means for sealing each of the pistons into its cylinder may comprise sealing means carried on the cylinder walls which engage and seal the walls of the piston, thus, the sealing means may be in the form of resilient sealing rings carried adjacent the mouth of the cylinder and the cylinder may be substantially part spherical.

In an alternative arrangement the means for sealing each of the pistons into its cylinder comprising sealing means carried on the cylinder.

In a preferred construction the invention set forth and described in the Applicant's copending U.K. Patent Application No.

16937/77 (Serial No. 1,603,199) is used, thus, one of the annular cylinders may be arranged to communicate freely with an annular compensation cylinder within which is an annular compensation piston which moves in sealing engagement therewith in a linear direction.

This particular construction thus enables any unwanted end movement of the pistons and cylinders to be accommodated in the compensation piston and cylinder because, the compensation cylinder can only move in a linear direction thus relieving pressures on the sealing means for the main pistons and cylinders.

The means for sealing the compensation piston into the compensation cylinder can again comprise sealing means carried on the cylinder walls which engage and seal the walls of the piston.

Thus, the sealing means may be in the form of resilient sealing rings carried adjacent the mouth of the compensation cylinder.

In an alternative arrangement the means for sealing the compensation piston into the compensation cylinder may comprise sealing means carried on the piston itself.

The cross-sectional area of the mouth of the compensation cylinder may be the same as or larger than the cross-sectional area of the annular cylinder.

The compensation cylinder may conveniently be an extension of the annular cylinder and the annular cylinder may have an outer wall which is substantially co-axial and in line with the outer wall of the compensation cylinder.

The compensation piston and cylinder can be carried on any of the various members as desired and in one convenient construction the compensation cylinder is carried on the female member and if desired the compensation piston can be carried on the annular connecting means.

In another arrangement the compensation piston can be carried on the female member and the compensation cylinder on the annular connecting means.

In another convenient arrangement the compensation cylinder can be provided on the male member in a position spaced away from the innermost end of the annular piston and communicate with the annular cylinder through a passage in said annular piston.

Again, the compensation cylinder can be arranged to communicate with said annular cylinder in one of the flexible assemblies and said compensation piston can be carried on the other flexible assembly.

If desired both joint assemblies can incor porate compensation pistons and cylinders.

Means can also be provided for protecting the surface of the pistons when they are exposed from their cylinders and this may comprise a fluid tight sleeve or sleeves which surround the external surfaces of the joint and contains or contain a lubricating medium.

The invention also includes a protective suit or apparatus incorporating a hollow flexible joint as set forth above.

The invention can be performed in many ways and a number of embodiments will now be described by way of example and with reference to the accompanying drawings in which: Figure 1 is a diagrammatic cross-sectional side elevation of an elbow joint for an armoured diving suit incorporating the invention; Figure 2 is a diagrammatic cross-section of an alternative construction; and, Figure 3 and Figure 4 are cross-sectional views of further constructions according to the invention.

As shown in Figure 1 the joint embodies the invention set forth in United Kingdom Patent Specification No. 1,332,902. The joint is an elbow joint for a submersible armoured diving suit and comprises two annular male members 1 and 2 which are housed for angular movement within, respectively, annular female members 3 and 4. Thus, there are two flexible assemblies, one comprising members 1 and 3 and the other comprising members 2 and 4.

The annular female members are connected together by annular connection means in the form of a collar 5 the ends 6 and 7 of which are inclined to each other and have attached to them part-spherical annular cylinders 8 and 9. The male members 1 and 2 are provided with annular part-spherical pistons 10 and 11 which are angularly movable in the part-spherical cylinders 8 and 9. The inner surface 12 and the outer surface 13 of each of the pistons are parallel and co-operate with annular resilient sealing rings 15 and 16 which are carried on the inner wall 17 and outer wall 18 of the cylinders 8 and 9 adjacent the mouth of each cylinder. The part spherical cylinders 8 and 9 are each filled with a hydraulic fluid such as oil or glycerine, by means of an opening (not shown) which is subsequently closed and sealed. Thus each annular part-spherical piston 10 and 11 has a longitudinal axis which can move angularly in relation to the longitudinal axis of its respective annular part-spherical cylinder 8 and 9. Each flexible assembly has a central position in which the longitudinal axis of its piston is axially in line with the longitudinal axis of its cylinder. The positions of the aligned axes in each flexible assembly is indicated by chain lines A and B in Figure 1 and it will be seen that those axes are normal to the ends 6 and 7 of the collar 5 so that they are angularly inclined to each other when the assemblies are in their central positions.

As shown in solid lines in the drawing the cylinders 10 and 11 are in a position in which a passage extending continuously through the joint is substantially straight. The position in which the axes of the annular members are at their smallest included angle is indicated in broken lines, the positions of the axes being indicated by the letters C and D. The amount of angular movement of each piston within its cylinder is approximately 500, the angle be tween the end faces 6 and 7 of the annular collar 5 is approximately 300 so that when the axes of the male members are in the positions indicated by C and D the angle between the axes is approximately 90". In the arrangement shown in Figure 1 the stroke of the pistons in the cylinders is such that each male member can be moved backwards away from the straight line position by approximately 5 as indicated by lines E and F thus leaving 45" of movement in the other direction to achieve the combined 90" angle between the male members when they are closed together.

It will be appreciated that the angle between the axes C and D will depend upon the stroke of the pistons 10 and 11 within the cylinders 8 and 9 and the angle between the ends 6 and 7 of the collar 5.

As mentioned above the construction described and shown in Figure 1 employs the invention set forth in the Applicant's British Patent No. 1,332,902 but if desired the seals could be carried by the pistons in a construction such as that set forth in the Applicant's earlier Patent No. 400386.

In Figure 2 an alternative construction is shown but the same reference numerals are used to indicate similar parts.

The general construction of the cylinders 8 and 9 and pistons 10 and 11 is similar to that shown in Figure 1 but in this arrangement the collar 5 is arranged to provide an extension of the part-spherical cylinder 8 by an annular compensation cylinder 20 having walls 21 and 22 which are straight and parallel to its axis.

The ends of the cylinder 9 are extended to provide a straight sided annular compensation piston 23. The inner wall 24 and outer wall 25 of this compensation piston seal against annular resilient sealing rings 26 and 27 carried on the walls at the mouth of this compensation cylinder. The annular partsperical cylinder 8 communicates freely through openings 28 with the annular straight sided compensation cylinder 20 and the crosssectional area of the mouth of the cylinder 8 is arranged to be the same as the cross-sectional area of the mouth of the compensation cylinder 20 so that when pressure is applied externally and an equal and opposite pressure exerted by the fluid in the cylinder 8 any loss of fluid in the cylinder will be compensated by the annular compensation piston 20 moving with a linear motion. As compression increases with pressure any tendency for the partspherical piston 10 or the part-spherical piston 11 to move in a linear direction into the partspherical cylinder 8 or 9 respectively will be obviated by linear movement of the annular compensation piston 23 thus ensuring that the seals 15 and 16 on both cylinders are not damaged and the part-spherical piston does not jam.

The use of such a cylindrical compensation cylinder and piston having a linear movement in combination with a part-spherical piston and cylinder is described and claimed in the Applicant's co-pending British Patent Application No. 16937/77 (Serial No. 1,603,199).

Once again it will be appreciated that the sealing between the pistons and the cylinders could be achieved by carrying seals on the pistons themselves rather than on the cylinder walls.

The arrangement shown in Figure 3 also utilises compensation pistons with a linear movement to compensate for end pressures and this embodiment utilises a construction in which the annular cylinders themselves are not part-spherical. The same reference numerals are used in this embodiment to indicate similar parts to those in Figures 1 and 2 but in this construction two annular compensation cylinders are provided which are indicated by reference numeral 30. Each of the cylinders 8 and 9 has a straight outer wall 31 which is substantially co-axial and aligned with the straight outer wall 32 of each of the annular compensation cylinders 30. As will be seen from the drawing the outer wall 32 is substantially a continuation of the wall 31.

The collar 5 carries two annular compensation pistons indicated by reference numerals 33 and these are located within the compensation cylinders 30 and seal against sealing rings 34 and 35 carried adjacent the mouths of the compensation cylinders 30. The mouths of the compensation cylinders 30 are of larger crosssectional area than the mouths of the annular cylinders 8 and 9 and the cylinders 8 and 9 are not part-spherical as in the earlier embodiments shown in Figures 1 and 2 so that when pressure is applied externally and equal and opposite pressure is exerted by the fluid in the annular cylinders 8 and 9 any tendency for the part-spherical pistons 10 and 11 to move in a linear direction into the cylinders 8 and 9 is obviated as in the embodiment shown in Figure 2 but the larger cross-sectional area of the compensation pistons 33 tends to cause them to move first if there is any tendency for either piston to move at all.

Retaining rings 36 are provided having inwardly projecting flanges 37 which act tu retain the female members 3 and 4 by engag ing against outwardly projecting flanges 8.

In yet another construuction (not shown) the location of the compensation cylinders and pistons could be as shown in Figure 3 of the Applicant's co-pending British Patent Application No. 16937/77 (Serial No.

1,603,199).

Figure 4 shows a construction which operates in a somewhat similar fashion to Figure 2 and similar reference numerals are used to indicate similar parts. In this arrange ment however the annular compensation cylin der 40 is not parallel to the general longitudinal axis of the joint but is axially aligned with the general axis of the part-spherical annuular cylinder 9. It will also be seen that the collar 5 is omitted and a compensation piston 42 is carried as an extension of the annular cylinder 8. The compensation cylinder 40 communicates with the annular cylinder 8 through a series of passages 43 in the piston 42 and also through a further series of passages 44 with the cylinder 9 so that there is a balance across the joint.

The compensation piston 42 and compensation cylinder 40 and the parts connecting them to the annular cylinders 8 and 9 therefore provide annular connection means. In order to limit the movement of the compensation cylinder 42 a series of retaining bolts 45 are provided which are a sliding fit in a flange 46 and are screwed into tapped blind openings 47 in the female member 3.

In this construction the included angle between the axes of the two flexible assemblies at their central positions is 1450 and each of the male members 1 and 2 has a range of angular movement of 35". The position of the male member at their most acute angle is shown in broken lines and is 110 and their positions in the opposite direction are shown in full lines. It will be seen that there is a substantially straight passage through the joint in this open position and in the acute angle position they are not very far displaced from a right angle. The maximum range of movement of the joint is therefore 70" which is sufficient for most operational purposes in an elbow joint.

Although the arrangements described above are intended for use with an elbow joint of an armoured suit joints according to the invention can be used in any of the flexible joints required in protective suits or apparatus.

The term "protective suit or apparatus" is used herein not only to include suits having arms and legs by which the occupant such as a diver, is protected but also a chamber from which mobile limbs project or, indeed any kind of protective apparatus for which such a joint is required.

Such a flexible joint can also be incorporated in a suit for working in pressurised atmosphere or vacuum atmosphere such as one encountered in space activities, or be employed wherever there is requirement for a hollow flexible joint which is subjected to an internal/external pressure differential, for example a pipe line.

WHAT I CLAIM IS: 1. A hollow flexible joint for use with

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. with pressure any tendency for the partspherical piston 10 or the part-spherical piston 11 to move in a linear direction into the partspherical cylinder 8 or 9 respectively will be obviated by linear movement of the annular compensation piston 23 thus ensuring that the seals 15 and 16 on both cylinders are not damaged and the part-spherical piston does not jam. The use of such a cylindrical compensation cylinder and piston having a linear movement in combination with a part-spherical piston and cylinder is described and claimed in the Applicant's co-pending British Patent Application No. 16937/77 (Serial No. 1,603,199). Once again it will be appreciated that the sealing between the pistons and the cylinders could be achieved by carrying seals on the pistons themselves rather than on the cylinder walls. The arrangement shown in Figure 3 also utilises compensation pistons with a linear movement to compensate for end pressures and this embodiment utilises a construction in which the annular cylinders themselves are not part-spherical. The same reference numerals are used in this embodiment to indicate similar parts to those in Figures 1 and 2 but in this construction two annular compensation cylinders are provided which are indicated by reference numeral 30. Each of the cylinders 8 and 9 has a straight outer wall 31 which is substantially co-axial and aligned with the straight outer wall 32 of each of the annular compensation cylinders 30. As will be seen from the drawing the outer wall 32 is substantially a continuation of the wall 31. The collar 5 carries two annular compensation pistons indicated by reference numerals 33 and these are located within the compensation cylinders 30 and seal against sealing rings 34 and 35 carried adjacent the mouths of the compensation cylinders 30. The mouths of the compensation cylinders 30 are of larger crosssectional area than the mouths of the annular cylinders 8 and 9 and the cylinders 8 and 9 are not part-spherical as in the earlier embodiments shown in Figures 1 and 2 so that when pressure is applied externally and equal and opposite pressure is exerted by the fluid in the annular cylinders 8 and 9 any tendency for the part-spherical pistons 10 and 11 to move in a linear direction into the cylinders 8 and 9 is obviated as in the embodiment shown in Figure 2 but the larger cross-sectional area of the compensation pistons 33 tends to cause them to move first if there is any tendency for either piston to move at all. Retaining rings 36 are provided having inwardly projecting flanges 37 which act tu retain the female members 3 and 4 by engag ing against outwardly projecting flanges 8. In yet another construuction (not shown) the location of the compensation cylinders and pistons could be as shown in Figure 3 of the Applicant's co-pending British Patent Application No. 16937/77 (Serial No.

1,603,199).

Figure 4 shows a construction which operates in a somewhat similar fashion to Figure 2 and similar reference numerals are used to indicate similar parts. In this arrange ment however the annular compensation cylin der 40 is not parallel to the general longitudinal axis of the joint but is axially aligned with the general axis of the part-spherical annuular cylinder 9. It will also be seen that the collar

5 is omitted and a compensation piston 42 is carried as an extension of the annular cylinder 8. The compensation cylinder 40 communicates with the annular cylinder 8 through a series of passages 43 in the piston 42 and also through a further series of passages 44 with the cylinder

9 so that there is a balance across the joint.

WHAT I CLAIM IS: 1. A hollow flexible joint for use with

apparatus subject to an internal/external pressure differential comprising first and second flexible assemblies, each assembly having an annular male member movable within an annular female member, the male member having an annular piston which can move angularly in sealing engagement in an annular cylinder carrying a sealing liquid in the female member, said annular piston and cylinder having longitudina axes which can move angularly in relation t each other and said flexible assembly havir a central position in which the longitudinal axis of its piston is axially in line with the longitudinal axis of the cylinder the axes of the flexible assemblies being angularly inclined to each other when the flexible assembles are in their central positions, and the male and female members and the annular connecting means being arranged to provide a continuous passage through them at all angles of the joint.

2. A hollow flexible joint as claimed in claim 1 in which the angle between the longitudinal axes of the flexible assemblies when in the central positions, and the operating stroke of the annular pistons in them are arranged, so that when both pistons are located in positions in which the angle between the movable outer member is at a maximum the axis of the passage through them is substantially straight.

3. A hollow flexible joint as claimed in claim 1 or claim 2 in which the longitudinal axes of the asemblies when in their central positions are inclined to each other at an angle between 165 and 1350.

4. A hollow flexible joint as claimed in claim 3 in which the annular cylinders are carried by the annular connecting means and their axes are inclined to each other at an angle between 1600 and 1500.

5. A hollow flexible joint as claimed in claim 4 in which the relative angular movement between each annular male member and its associated female member is between 15 and 45".

6. A hollow flexible joint as claimed in claim 5 in which the relative angular movement between each annular male member and its associated female member is between 200 and 40 .

7. A hollow flexible joint as claimed in any one of the preceding claims in which the annular connecting means comprises a collar the ends of which are inclined to each other and to which the flexible assemblies are connected.

8. A hollow flexible joint as claimed in any one of the preceding claims in which the means for sealing each of the pistons into its cylinder comprises sealing means carried on the cylinder walls which engage and seal the walls of the piston.

9. A hollow flexible joint as claimed in claim 9 in which the sealing means are resilient sealing rings carried adjacent the mouth of the cylinder.

10. A hollow flexible joint as claimed in claim 9 in which the cylinder is substantially part spherical.

11. A hollow flexible joint as claimed in any one of preceeding claims 1 to 7 in which the means for sealing each of the pistons into its cylinder comprises sealing means carried on the cylinder.

12. A hollow flexible joint as claimed in any one of the preceding claims in which one of said annular cylinders communicates freely with an annular compensation cylinder within which is an annular compensation piston which moves in sealing engagement therewith in a linear direction.

13. A hollow flexible joint as claimed in claim 12 in which the means for sealing the compensation piston in the compensation cylinder comprises sealing means carried on the cylinder walls which engage and seal the walls of the piston.

14. A hollow flexible joint as claimed in claim 13 in which the sealing means in the compensation cylinder are resilient sealing rings carried adjacent the mouth of the cylinder.

15. A hollow flexible joint as claimed in claim 12 in which the means for sealing the compensation cylinder comprise sealing means carried on the piston.

16. A hollow flexible joint as claimed in claims 12 to 15 in which the cross-sectional area of the mouth of the compensation cylinder is the same as or larger than the cross-sectional area of the first annular cylinder.

17. A hollow flexible joint as claimed in claims 12 to 15 in which the compensation cylinder is an extension of the annular cylinder.

18. A hollow flexible joint as claimed in claim 17 in which the annular cylinder has an outer wall which is substantially co-axial and in line with the outer wall of the compensation cylinder.

19. A hollow flexible joint as claimed in claims 12 to 17 in which the compensation cylinder is carried on the female member.

20. A hollow flexible joint as claimed in claim 18 in which the compensation piston is carried on the annular connecting means.

21. A hollow flexible joint as claimed in claims 12 to 17 in which the compensation piston is carried on the female member.

22. A hollow flexible joint as claimed in claim 21 in which the compensation cylinder is carried on the annular connecting means.

23. A hollow flexible joint as claimed in daims 12 to 17 in which the compensation cylinder is provided on the male member at a position spaced away from the innermost end of the annular piston and communicates with the annular cylinder through a passage in said annular piston.

24. A hollow flexible joint as claimed in claims 12 to 16, 19, 21 or 22 in which said compensation communicates with said annular cylinder in one of the flexible assemblies and said compensation piston is carried on the other flexible assembly.

25. A hollow flexible joint as claimed in claims 12 to 23 in which both joint assemblies incorporate compensation piston and cylinder.

26. A hollow flexible joint as claimed in claims 1 to 25 including means for protecting the surface of the pistons when they are exposed from their cylinders.

27. A hollow flexible joint as claimed in claim 26 in which said protecting means comprise a fluid tight sleeve or sleeves which surround the external surfaces of the joint and contains or contain a lubricating medium.

28. A hollow flexible joint substantially as described herein with reference to and as shown in Figures 1, 2, 3 or 4 of the accompanying drawings.

29. A protective suit or apparatus incorporating a hollow flexible joint as set forth in any one of the preceeding claims.