GB1603199A

GB1603199A - Hollow flexible joint

Info

Publication number: GB1603199A
Application number: GB1693777A
Authority: GB
Original assignee: Peress J S
Current assignee: Peress J S
Priority date: 1978-05-02
Filing date: 1978-05-02
Publication date: 1981-11-18

Description

(54) HOLLOW FLEXIBLE JOINT (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 connection 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.

400,386 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 to 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 that in joints of the latter type which carry sealing rings adjacent the mouth of the cylinder there tends to be a small linear movement of the piston within the cylinder, that is, the male member carrying the piston tends to move slightly towards the female member and this movement can cause binding in the joint and/or damage to the seals as they tend to spread. The present invention is intended to overcome this difficulty.

According to the present invention a hollow flexible joint for use with apparatus subjected to an internal/extemal pressure differential comprises an annular male member movable within an annular female member, the male member having an annular part-spherical piston which moves in sealing engagement within a first annular cylinder carrying a sealing liquid in the female member, said first annular cylinder communicating freely with a second annular cylinder.

and a second annular piston located in said second cylinder which moves in sealing engagement therein in a linear direction.

The cross sectional area of the mouth of the second cylinder can be arranged to be the same as or larger than the cross-sectional area of the first cylinder and the means for sealing the annular part-spherical piston into the first cylinder can be carried on the cylinder walls and engage and seal the walls of the piston.

With this arrangement the sealing means can be resilient sealing rings carried adjacent the mouth of the cylinder.

In one preferred construction the first cylinder is substantially part-spherical but in another preferred construction the first cylinder can have an outer wall which is substantially co-axial and in line with the outer wall of the second cylinder, the cross-sectional area of the mouth of the second cylinder being greater than the cross-sectional area of the mouth of the first cylinder.

In any case, the means for sealing the sec ond piston into the second cylinder can also be carried on the cylinder walls and engage and seal the wall of the piston and once again the sealing means may comprise resilient seal ing rings carried adjacent the mouth of the cylinder.

The arrangement is such that any compress ing movement of the joint would tend to be accommodated by movement of the second piston because its movement is linear and if there is any loss of fluid in the joint this will also be accommodated by movement of the second piston.

In one convenient embodiment the second annular cylinder is carried on the female member and the second annular piston is carried on an annular piston support. With this arrangement therefore the second annular cylinder may be provided as an extension of the first annular cylinder.

In another embodiment the second annular cylinder is carried on the male member and the second annular piston is carried on an annular piston support. With this arrangement the second annular cylinder may be provided on the male member at a position spaced away from the innermost end of the partspherical piston and communicates with the first cylinder through a passage in said partspherical piston.

With the latter arrangement the passage may open into the part-spherical cylinder through the piston face.

In yet another preferred construction the second annular piston is carried on the female member and the second annular cylinder is carried on an annular cylinder support.

With this arrangement as with the arrangement in which the second annular cylinder is carried on the female member the second cylinder may communicate with the first through a series of ports.

In order to reduce friction the inner annular surface of the second annular piston may be coated with a synthetic plastics material such as polytetrafluoroethylene.

Preferably means are also provided for protecting the surface of part-spherical piston when it is exposed from the first cylinder and this may be provided by a fluid tight flexible sleeve which surrounds the external surfaces of the joint and contains a lubricating medium, for example oil.

The joint is particularly useful for use with suits and apparatus subjected to an internal/ external pressure differential such as an armoured diving suit and the joint may therefore be provided with means for connecting it into a limb of a diving apparatus and the invention also includes a protective suit or apparatus incorporating the joints as set forth above.

The invention may be performed in many ways and various embodiments will now be described by way of example and with reference to the accompanying drawings in which: Figure 1 is a cross-sectional side elevation through a joint of an armoured diving suit incorporating the invention, Figure 2 is a cross-sectional side elevation of an alternative construction; Figure 3 is a cross-sectional side elevation of another alternative construction for the same type of joint; Figure 4 is a part cross-sectional side elevation of another alternative construction; and, Figure 5 is a part cross-sectional view of yet another construction 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 a wrist joint of a submersible armoured diving suit and comprises an annular male member 1 which is movably housed within an annular female member 2. Both members are partspherical and the male member 1 has an annular part-spherical piston 3 which is movable in a co-operating annular part-spherical cylin der 4 provided in the female member 2. The inner surface 5 and outer surface 6 of the piston are parallel and co-operate with annular resilient sealing rings 7 and 8 which are carried on the inner wall 9 and outer wall 10 of the cylinder 4 adjacent its mouth. The operative face 11 of the piston 3 is radial to the axis of the sphere which is indicated by reference numeral 12 and the head of the piston carrying the face 11 extends to one side of a plane passing diametrically through the axis of the joint and through the male member. The major portion of the length of the annular part-spherical cylinder extends to one side of a plane passing diametrically through the axis of the joint, such a plane being indicated by broken line 14.

The part-spherical cylinder 4 is filled with a hydraulic fluid such as oil or glycerene, by means of an opening (not shown) which is subsequently closed and sealed.

It will be seen from the drawing that the part-spherical piston extends for approximately equal angular distances about the centre of the joint and it can thus rotate in the female member about these angles. It can also revolve and any suitable hand or closure can be attached to its outer end.

The end of the part-spherical cylinder 4 is extended to form a second annular cylinder 20 having walls 21 and 22 which are straight and parallel to its axis. Located in this second annular cylinder 20 is a straight sided second annular piston 23. The inner wall 24 and the outer wall 25 of this piston 23 seal against annular resilient sealing rings 26 and 27 and the outer end of the piston is screw threaded at 28 to enable it to be screwed into annular piston support 29 whi which A provides the fore part of the arm of the suit. A retaining ring 30 has an inwardly projecting flange 31 which is screwed onto this support member and acts to retain the female member 2 by engaging against an outwardly projecting flange 32.

From the drawing it will be seen that the annular part-spherical cylinder 4 freely connects with the annular straight sided cylinder 20. The cross-sectional area of the mouth of the cylinder 4 is arranged to be the same as the cross-sectional area of the mouth of the cylinder 20 so that when pressure is applied externally and an equal opposite pressure exerted by the fluid in the cylinder 4 any loss of fluid in the cylinder will be compensated by the annular piston 23 moving downwardly with a linear motion. As compressability increases with pressure any tendency for the part-spherical piston 3 to move in a linear direction into the part-spherical cylinder 4 will be obviated by linear movement of the annular piston 23 thus ensuring that the seals 7 and 8 are not damaged and the part-spherical piston does not jam.

In an alternative construction as shown in Figure 2 the same reference numerals are used to indicate similar parts to those n Figure 1 but in this construction the second annular cylinder, indicated by reference numeral 20a has an outer wall 22a which is substantially co-axial and aligned with the outer wall 10 of a first cylinder 4a in which the partspherical piston 3 moves. It will be seen from the drawing that the wall 20a is substantially a continuation of the inner wall 10. The second piston, indicated by reference numeral 23a has an outer wall 25a which engages a seal 27 and the inner wall 24a engages the seal 26. It will be seen from the drawing that the mouth of the second cylinder 20a is of larger cross-sectional area than the mouth of the first cylinder 4a and this first cylinder is not part-spherical as in the embodiment shown in Figure 1 so that when pressure is applied externally and an equal and opposite pressure is exerted by the fluid in the cylinder 4a any tendency for the part-spherical piston 3 to move in a linear direction into the cylinder 4a is again obviated as in the first embodiment but the larger cross-sectional area of the piston 23a tends to cause it to move first if there is any tendency for either piston to move at all.

In the arrangement shown in Figure 1 the means for sealing the first part-spherical piston 3 are carried on the walls of the cylinder 4 but if desired an alternative construction could be used in which the piston 3 itself carried sealing means which engage the walls of the cylinder 4. With this arrangement the walls of the cylinder 4 would of course have to be parallel. Again the seals for the second piston could if desired be carried on the second annular piston 23 itself. In the arrangement shown in Figure 2, due to the shape of the first cylinder 4a it is necessary for the seals to be carried on the cylinder walls but if desired the sealing means for the piston 23a could be carried on the piston itself and engage the walls of the cylinder 20a.

In another construction according to the invention as shown in Figure 3 the same reference numerals are again used to indicate similar parts to those employed in Figure 1.

In this construction an annular piston 40 having an inner wall 41 and an outer wall 42 is located in a second annular cylinder 43.

This cylinder 43 carries sealing rings 44, 45 on its inner wall 46 and outer wall 47. The second annular cylinder 43 is provided on the male member 1 at a point spaced away from the operative face 11 of the piston 3.

A series of passages 47 are provided in the piston, these passages opening out of the operative face 11 and extending to the annular cylinder 43 so that there is free communication between the two cylinders.

The effect of this construction is similar to that described with regard to Figure 1, that is, the linear movement of the annular piston 40 will accommodate end loads and prevent linear movement of the part-spherical piston 3 in the part-spherical cyilnder 4.

In order to retain the male member on an annular piston support 50 which carries the piston 40 a retaining ring and flange. similar to that described in Figure 1 can be employed but in order to make the drawings more clear they have been omitted in Figure 3.

Figure 3 however shows means for protect ing the outer surface 6 of the part-spherical piston 3 when it is exposed from the part spherical cylinder 4. These means comprise a fluid tight flexible sleeve made for example from synthetic rubber indicated by reference numeral 51. The sleeve is provided in cor rugated form and one end is clamped ba retaining ring 52 around the outer surface of the piston support 50 and the other end is similarly clamped in position on the outer surface of the female part 2 by a similar clamping ring 53.

The sleeve 51 is filled with a lubricating medium, such as oil or glycerene through a filling opening which is closed by a cap 54.

As will be seen from Figure 3 the flexible sleeve expands and contracts as required according to movement of the suit but prevents exposure of the outer surface 6 of the piston 3 thus preventing scoring and damage or the ingress of sand or other material. The lubricating medium within the sleeve will of course respond to the external pressure exerted on the joint and balance it.

It will be appreciated that a similar sleeve can be provided on the arrangement shown in Figure 1 and Figure 2, or Figures 4 and 5 to be described.

Although in the construction shown in Figure 3 the cross-sectional area of the second cylinder 43 is the same as the cross-sectional area of the mouth of first cylinder 4 the dimensions could be arranged so that the crosssectional area of the cylinder 43 was greater than that of the cylinder 4.

In the construction shown in Figure 4 the same reference numerals are again used to indicate similar parts and the general operation of this construction is similar to that des cribed with regard to Figure 1 but in this case the second cylinder indicated by reference numeral 60 is provided as a separate cavity in the female member 2. This second annular cylinder 60 communicates with the first cylinder 4 through a series of ports 61 so that again there is a balancing of fluid. In this construction the second piston 63 is carried on an annular piston support 64 which is retained on the female member 2 by a series of locking screws 65. The screws are located in bores 66 in the support 64 and allow the support to move axially but to restrain its axial movement.

In order to assist sealing and prevent the ingress of dirt into the seal between the second piston 63 and the walls of the second cylinder 60 a flat sealing ring 67 is provided.

Figure 5 shows another alternative construction in which again the same reference numerals are used to indicate similar parts.

In this construction the second piston, indicated by reference numeral 70, is carried on the female part 2 and is located in a second annular cylinder 71 provided in an annular cylinder support 72. The cylinder 70 is sealed into the annular piston 71 by sealing rings 26, 27 carried on the walls of the cylinder and in order to provide a fluid transfer between the first cylinder 4 and the second cylinder 71 a series of ports 72 are provided in the second piston 70.

A flat synthetic plastics material sealing ring 73 is carried on extension 74 of the inner wall of the second cylinder 71 and acts to seal between the extension 74 and the wall of the piston. With this construction as in all the other constructions the inner wall of the second cylinder can be coated with a synthetic plastics material, such as polytetrafluoroethylene in order to reduce friction and prevent jamming and this sealing ring 73 also assists in this manner.

In order to locate the support 72 on the female member 2 a series of retaining bolts 75 are provided which extend through bores 76 in the support and this limit its axial movement.

Although all the arrangements described above are intended for use with a wrist joint of an armoured diving suit the 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 a pressurised atmossphere or a vacuum atmosphere such as is encountered in space activities, or be employed wherever there is a 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 apparatus subjected to an internal/external pressure differential comprising an annular male member movable within an annular female member, the male member having an annular part spherical piston which moves in sealing engagement within a first annular cylinder carrying a sealing liquid in the female member, said first annular cylinder communicating freely with a second annular cylinder and a second annular piston located in said second cylinder which moves in sealing engagement therein in a linear direction.

2. A hollow flexible joint as claimed in claim 1 in which the cross sectional area of the mouth of the second cylinder is the same as or larger than the cross-sectional area of the first cylinder.

3. A hollow flexible joint as claimed in claim 1 or claim 2 in which the means for sealing the annular part spherical piston into the first cylinder is carried on the cylinder walls and engage and seal the walls of the piston.

4. A hollow flexible joint as claimed in claim 3 in which the sealing means are resilient sealing rings carried adjacent the mouth of the cylinder.

5. A hollow flexible joint as claimed in claim 3 or claim 4 in which the first cylinder is substantially part spherical.

6. A hollow flexible joint as claimed in claims 2-5 in which the first cylinder has an outer wall which is substantially co-axial and in line with the outer wall of the second cylin der, the cross-sectional area of the mouth of the second cylinder being greater than the cross-sectional area of the first cylinder.

7. A hollow flexible joint as claimed in claims 1-6 in which the means for sealing the second piston into the second cylinder is carried on the cylinder walls and engage and seal the wall of the piston.

8. A hollow flexible joint as claimed in claim 7 in which the sealing means for the second piston are resilient sealing rings carried adjacent the mouth of the cylinder.

9. A hollow flexible joint as claimed in any one of the preceding claims 1 to 8 in which said second annular cylinder is carried on the female member and the second annular piston is carried on an annular piston support.

10. A hollow flexible joint as claimed in claim 9 in which the second annular cylinder is an extension of the first annular cylinder.

11. A hollow flexible joint as claimed in any one of - the preceding claims 1 to 9 in which the second annular cylinder is carried on the male member and the second annular

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. cribed with regard to Figure 1 but in this case the second cylinder indicated by reference numeral 60 is provided as a separate cavity in the female member 2. This second annular cylinder 60 communicates with the first cylinder 4 through a series of ports 61 so that again there is a balancing of fluid. In this construction the second piston 63 is carried on an annular piston support 64 which is retained on the female member 2 by a series of locking screws 65. The screws are located in bores 66 in the support 64 and allow the support to move axially but to restrain its axial movement. In order to assist sealing and prevent the ingress of dirt into the seal between the second piston 63 and the walls of the second cylinder 60 a flat sealing ring 67 is provided. Figure 5 shows another alternative construction in which again the same reference numerals are used to indicate similar parts. In this construction the second piston, indicated by reference numeral 70, is carried on the female part 2 and is located in a second annular cylinder 71 provided in an annular cylinder support 72. The cylinder 70 is sealed into the annular piston 71 by sealing rings 26, 27 carried on the walls of the cylinder and in order to provide a fluid transfer between the first cylinder 4 and the second cylinder 71 a series of ports 72 are provided in the second piston 70. A flat synthetic plastics material sealing ring 73 is carried on extension 74 of the inner wall of the second cylinder 71 and acts to seal between the extension 74 and the wall of the piston. With this construction as in all the other constructions the inner wall of the second cylinder can be coated with a synthetic plastics material, such as polytetrafluoroethylene in order to reduce friction and prevent jamming and this sealing ring 73 also assists in this manner. In order to locate the support 72 on the female member 2 a series of retaining bolts 75 are provided which extend through bores 76 in the support and this limit its axial movement. Although all the arrangements described above are intended for use with a wrist joint of an armoured diving suit the 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 a pressurised atmossphere or a vacuum atmosphere such as is encountered in space activities, or be employed wherever there is a 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 apparatus subjected to an internal/external pressure differential comprising an annular male member movable within an annular female member, the male member having an annular part spherical piston which moves in sealing engagement within a first annular cylinder carrying a sealing liquid in the female member, said first annular cylinder communicating freely with a second annular cylinder and a second annular piston located in said second cylinder which moves in sealing engagement therein in a linear direction.

piston is carried on an annular piston support.

12. A hollow flexible joint as claimed in claim 11 in which the second annular cylinder is provided on the male member at a position spaced away from the innermost end of the part spherical piston and communicates with the first cylinder through a passage in said part spherical piston.

13. A hollow flexible joint as claimed in claim 12 in which the innermost end of the part spherical piston has a piston face through which said passage opens into the first cylinder.

14. A hollow flexible joint as claimed in any one of preceding claims 1 to 9 in which the second annular piston is carried on the female member and the second annular cylinder is carried on an annular cylinder support.

15. A hollow flexible joint as claimed in claim 9 or claim 14 in which the second annular cylinder communicates with the first annular cylinder through a series of ports.

16. A hollow flexible joint as claimed in any one of the preceding claims in which the inner annular surface of the second annular piston is coated with a synthetic plastics material.

17. A hollow flexible joint as claimed in claim 16 in which the synthetic plastics material is polytetrafluoroethylene.

18. A hollow flexible joint as claimed in any one of the preceding claims including means for protecting the surface of the part spherical piston when it is exposed from the first cylinder.

19. A hollow flexible joint as claimed in claim 18 in which the protecting means comprise a fluid tight flexible sleeve which surrounds the external surface of said joint and contains a lubricating medium.

20. A hollow flexible joint as claimed in any one of the preceding claims provided with means for connection as a joint into a limb of a diving apparatus.

21. A hollow flexible joint substantially as described herein with reference to and as shown in Figure 1, Figure 2, Figure 3, Figure 4 or Figure 5 of the accompanying drawings.

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