GB2164404A

GB2164404A - A pipe coupling

Info

Publication number: GB2164404A
Application number: GB08522314A
Authority: GB
Inventors: Alan Belk
Original assignee: Bridon PLC
Current assignee: Bridon PLC
Priority date: 1984-09-10
Filing date: 1985-09-09
Publication date: 1986-03-19
Also published as: GB2164404B; GB8422808D0; GB2164403A; GB8522314D0; GB2164403B; GB8522313D0

Abstract

A pipe coupling (1) comprising an apertured flange sealing face (3), at least one movable mounted clamping hook (8) having a main body portion (10) and a cam follower portion (11) pivotally connected to the main body portion (10) and a turnable cam ring (5) having cam surface means (6) engageable with the or each cam follower portion (11) for moving the clamping hooks (8) on turning the cam ring (5). <IMAGE>

Description

1 GB2164404A 1

SPECIFICATION

A pipe coupling This invention relates to a pipe coupling and in particular to a pipe coupling of the kind comprising an axis, an apertured flange sealing face extending transversely of the axis, at least one movabiy mounted clamping hook comprising a main body portion and a cam follower means, and a turnable cam ring hav ing camming surface means engageable with said cam follower means for moving the.

clamping hook(s). Hereinafter such a pipe cou pling will be referred to as---apipe coupling of 80 the kind referred to---.

In EP-A-0092327 there is disclosed a known pipe coupling of the kind referred to having pivotally mounted clamping hooks each provided with a substantially flat surface con- 85 stituting the cam follower means. In this known pipe coupling the cam ring is provided with generally part helical camming surface means which, on turnina of the cam rina in a Preferably the cam ring is mounted for turning through an angle of less than 360'. Preferably the turning angle is less than 360'/n, where n is the number of clamping hooks, so that if three clamping hooks are provided, the turning angle will be no greater than 120', e.g. from 30' to 120'. - Conveniently the or each pivoted cam follower means and the associated camming sur- face means are slidably keyed together. For example one of the keyed together parts (e.g. the camming surface means) may comprise a cam slot, e.g. of T-shaped crosssection, and the other of the keyed together parts (e.g. the cam follower means) may comprise an interengaged part, e.g. of T-shaped crosssection, captively slidably received in the cam slot. Alternatively, the or each cam follower means may be resiliently urged against the camming surface means so as to make substantially planar face- to-face contact therewith. For example if more than one movable clamping hook is provided, the cam ring may include separate cam means for each clamping hook, given direction, contact the flat surfaces of the 90 each cam means having an axial through slot, cam follower means and pivot the clamping hooks radially inwards. However, as the clamping hooks pivot radially inwards the angles that the flat surfaces constituting the cam follower means make relative to the longitudinal axis of the pipe coupling vary. To ensure good face-to-face contact between the camming surface means of the cam ring and the cam follower means of the clamping hooks, it is thus necessary, in this known pipe 100 coupling, to correspondingly vary the cam angles of the generally part helical camming means. As a result the camming surface means, which control the inward pivotal movements of the clamping hooks, follow a complex contour which is difficult and relatively expensive to manufacture.

The present invention aims to provide a pipe coupling of the kind referred to in which the camming surface means are of simplified design.

According to the present invention a pipe coupling of the kind referred to is characterised in that the, or at least one of the, cam follower means is pivotally connected to its associated main body portion.

By providing a cam follower means which is pivoted to the main body portion of the clamping hook, the contacting camming sur- face means of the cam ring can be designed to have a part cylindrical or other surface formed by movement around the axis of the pipe coupling of a straight line disposed parallel to, or at a constant angle relative to, the axis. In particular such camming surface means are relatively easy to machine compared with the more complex contours required for the camming surface means of the cam ring of the pipe coupling described in EP- A-0092327.

extending substantially in a helical direction of the cam means through an angle typically less than 120', e.g. from 30' to 110'. The or each cam follower means has a bolt con- nected thereto which passes through a respective one of the slots of the cam means. Helical springs, coaxially arranged around the bolts, ensure that the pivoted cam follower means are resiliently urged against their respective cam means.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a schematic side view of one embodiment of a pipe coupling according to one aspect of the invention, Figures 2 and 3 are schematic side views of a clamping hook of the pipe coupling shown in Figure 1 with its cam follower means posi- tioned, respectively, in an axially outer position and an axially inner position, Figures 4 and 5 are schematic side views of a clamping hook of another embodiment of a pipe coupling according to one aspect of the invention, the clamping hook being shown, respectively, in an axially outer position and an axially inner position, Figure 6 is an axial sectional view of a further embodiment of a pipe coupling according to the invention and showing a pivoted clamping hook with its flange engaging head in a radially inner position, and Figure 7 is an axial sectional view, on an enlarged scale, of part of the pipe coupling shown in Figure 6 and showing the pivoted clamping hook with its flange engaging head in a radially outer position.

Figure 1 shows one embodiment of a pipe coupling, according to one aspect of the in- vention, generally designated by the reference 2 GB2164404A 2 numeral 1. The pipe coupling 1 has an end flange 2 defining an apertured flange sealing face 3 extending transversely, e.g. perpendicular, to the longitudinal axis 4 of the pipe cou5 pling.

A cam ring 5 is mounted on the pipe coupling 1 for turning movement about the axis 4. The cam ring 5 has three substantially helically disposed, spaced apart cams 6 which each extend through an angle preferably not exceeding 120' (so as not to overlap each other) end each of which is provided with an axial through slot 7 which extends in the helical direction for a major part of the helical extent of the cam 6.

Three clamping hooks 8 are arranged around the pipe coupling 1, the clamping hooks 8 being mounted on brackets 9 fixed at equally spaced positions around the end flange 2. Each clamping hook 8 comprises a main body portion 10 and a cam follower means 11 pivotally connected thereto by means of a pivot pin 12. Each main body portion 10 has a flange engaging head 13 and a cam slot 14 in which is received a fixed pin 15 carried by the bracket 9. The cam slot 14 consists of a substantially straight first slot portion 14a fflhich extends generally in the lengthwise direction of the main body portion 10 and a substantially straight second slot portion 14b arranged at an angle to the first slot portion 14a.

Each pivoted cam follower means has a bolt 16 fixed thereto which passes in a generally axial direction through the slot 7 formed in its associated helical cam 6. As can be seen more clearly in Figures 2 and 3, the slot 7 in each cam 6 is of stepped form, a part 7a of tha slot 7 which opens into the surface of the cam 6 facing towards the and flange 2 having a greater radial width than a part 7b of the slot which opens into a camming surface 17 which makes substantially face-to-face contact with a confronting surface of its associated cam follower means. The follower means 11 are resiliently urged against the camming surfaces 17 by helical compression springs 18 which coaxially surround the bolts 16 and are seated within the parts 7b of the slots 7.

Nuts 19 are provided on the ends of the bolts 16 to retain the helical compression springs 18 on the shanks of the bolts 16 and to enable adjustment of the resilient force provided by the springs 18 for resiliently urging the pivoted cam follower means 11 against the camming surfaces 17.

In use, the pipe coupling 1 is fixed, e.g. welded. at 20 to one end of a pipe (not shown) and is employed. to clamp a flange 21 of a pipe 22 (shown in chain lines in Figures 1 to 3) in a leak-tight manner to the apertured flange sealing face 3. Clamping and release of the flange 21 is achieved by turning the cam ring 5 through approximately 120' between first and second angular positions. Although not shown, the cam ring 5 may be manually turned (e.g. in a manner similar to that described with reference to GB-A-2098295) or turned with the aid of power means (e.g. as described with reference to GB-A-2098296).

In particular, Figure 1 shows the cam ring 5 in its second angular position with each pivoted cam follower means T1 in an axially inner position in face-to-face engagement with an end region of its associated camming surface 17. The cams 6 ensure that the flange engaging heads 13 of the clamping hooks 8 apply substantially axial clamping pressure on the rear annular face of the flange 21 to press the flange 21 into leak-tight engagement with the flange sealing face 3. On turning of the cam ring 5 in a counter-clockwise direction (as viewed when facing the flange sealing face 3-i.e. from the left-hand side of Figure 1), the bolts 16 move relatively along their respective slots 7. In view of the substantially helical arrangement of the cams 6 and because the bolts 16 and helical compression springs 18 hold the cam follower means 11 in contact with the camming surfaces 17, the means 11 are moved in a substantially axial direction, as the cam ring 5 is turned, until the cam ring 5 reaches its first angular position (e.g. a limit position) in which each cam follower means 11 is in an axially outer position (see Figure 2) in face-to-face engagement with an opposite end region of its associated camming surface 17.

During axial movement of each cam follower means 11 from its axially inner position to its axially outer position, occasioned by turning of the cam ring 5 from its second angular position to its first angular position, the clamping hooks 8 are moved relative to their mounting brackets 9 in axial planes. The actual movement of each clamping hook 8 is controlled by relative travel of each pin 15 along its associated cam slot 14. In particular, during turning of the cam ring 5 from its second angular position to an intermediate angular position between the first and second angular positions, each pin 15 travels along its associated first slot portion 14a so that the clamping hooks 8 and their flange engaging heads 13 move in substantially axial directions. At the intermediate angular position of the cam ring 5, each pin 15 is located at the angle between the first and second slot portions 14a and 14b, respectiely. As the cam ring 5 is turned from its intermediate position into its first position, each pin 15 enters the second slot portion 14b of its associated cam slot 14. As the pins 15 move relatively along the second slot portions 14b, the main body por- tion 10 of each clamping hook 8 pivots outwardly (i.e. in a clockwise direction as viewed in Figure 1) about the pivot pin 12 so that the flange engaging heads 13 are moved radially and axially outwardly. This radial outward movement of the flange engaging heads 13 3 GB2164404A 3 enables the flange 21 of the pipe 22 to be decoupled and removed from the pipe coupling 1 (or, alternatively, for a pipe flange 21 to be positioned adjacent the flange sealing face 3 ready to be coupled to the pipe coupiing 1) when the cam follower means 11 are in their axially outer positions.

On turning of the cam ring 5 back from its first angular position to its second angular po- sition, the surfaces 17 urge the cam follower means 11 to move from their axially outer positions to their axially inner positions. During turning of the cam ring 5 from its first position to its intermediate position, the flange en- gaging heads 13 are moved radially and axially inwards as the pins 15 travel relatively along the socond slot portion 14b of the cam slots 14. During turning of the cam ring 5 from its intermediate position towards its second posi- tion, the pins 15 travel relatively along the first slot portions 14a so that the main body portions 10 and the flange engaging heads 13 move substantially axially to enable clamping pressure to be applied to the rear annular face of the flange 20 so that the latter is pressed into leak-tight engagement with the flange sealing face 3.

Each cam 6 has a varying cam angle, the surface 17 of each cam which engages the cam follower means 11 being steeper when the cam ring 5 is turned between its first and intermediate positions than when the cam ring is turned between its second and intermediate positions (i.e. over a---hookclamping range---).

Releasable locking means (not shown) may be 100 provided for locking the cam ring in its second position (and, if required, in its first position). However, such locking means are usually not required if the cam angle of each cam 6, over the hook clamping range, is less than 7'. 105 Although all three clamping hooks 8 have been described as incorporating second slot portions 14b for providing radial outward movement of all three flange engaging heads 13 as the cam ring 5 is turned from its intermediate angular position to its first angular position, it will be appreciated that this is not essential.

Indeed a pipe flange 21 can be removed from, or inserted into, a pipe clamping position adjacent the flange sealing face 3 if only one or two of the flange engaging heads 13 are positioned in a radially outer position when the cam ring 5 is in its first position.

Furthermore it is not essential for the first and second cam slot portions 14a and 14b to be straight. Indeed the or each cam slot 14 could be curved, e.g. arcuate, with one end of the slot (i.e. the first slot portion) providing substantially, although not solely, axial movement and the other end of the slot (i.e. the second slot portion) providing a component of transverse or radial motion.

It will also be appreciated that although the coupling 1 has three clamping hooks 8, any convenient number of clamping hooks may be provided.

Figures 4 to 7 show other embodiments of pipe couplings according to the invention and, where possible, the same reference numerals have been used to identify similar parts in the various pipe couplings.

Figures 4 and 5 show a pipe coupling generally designated by the reference numeral 40. As with the pipe coupling 1, the pipe coupling 40 has three clamping hooks 8 each comprising a main body portion 10 and a pivoted cam follower means 11. However, each main body portion 10 of the pipe coupling 40 is not provided with a cam slot, but instead has profiled external cam surfaces 41a and 41b for engaging, respectively, a cam follower roller 47, rotatable about a fixed axis, and part of the flange 2. In particular each cam surface 41 a has a first portion 42 and a second portion 43 meeting the first portion 42 at an angle at point 44. The cam ring 5 of the pipe coupling 40 has three spaced apart helical or axially expanding cams 6 each having a helically extending slot 45 opening into its circumferential surface. The slots 45 have a generally T-shaped cross-section and have slidingly keyed therein correspondingly shaped portions 46 of the repsective pivoted cam fol- lower means 11 of the clamping hooks 8.

In use of the pipe coupling 40, turning of the cam ring 5 causes the cam follower means to be moved between an axially inner position (shown in Figure 5) when the cam ring 5 is in its second position and an axially outer position (shown in Figure 4) when the cam ring 5 is in its first position. The movement of each clamping hook 8 is controlled, as the cam ring 5 is turned, by engagement of the cam surface 41a or 41b, respectively, with the roller 47 or flange 2. During movement of the cam follower means between the axially inner position and the intermediate position, the first portion 42 engaging roller 47 controls the generally axial movement of the clamping hook 8. Movement of the cam follower means between the intermediate position and the axially outer position is controlled either by the cam surface 41b engaging flange 2 in the case where gravity causes a hook 8 to fall onto flange 2 or by the second portion 43 engaging roller 47 in the case where gravity causes hook 8 to fall onto the roller 47. In either case the flange engaging heads 13 move with a component of radial or transverse motion as the cam ring 5 is turned between its first and intermediate positions. When the cam ring 5 is in its intermediate position each roller 47 is positioned adjacent point 44 on each cam surface 41 a.

A further embodiment of a pipe coupling according to the invention is illustrated in Figures 6 and 7 which show a pipe coupling 1 generally designated by the reference numeral 50, having three clamping hooks 8 (only one 4 GB2164404A 4 of which is shown in Figures 6 and 7) each of which is mounted solely for pivotal movement about pin 15 relative to the flange sealing face 3. As with the other embodiments of pipe coupling described herein, it is of course' pos sible for any convenient number of clamping hooks to be provided. - The cam ring 5 is provided with three cam means 6 each engageable with a different one of the clamping hooks 8. Each cam means 6 has a radially varying first cam surface. 51 and an axially varying second cam surface 52. The first cam surface 51 is designed to make sub stantially face-to-face contact with a first cam follower means 11 pivotally connected to the 80 main body portion 10 of the clamping hook 8.

The second cam surface 52 is designed to contact a second cam follower means 53 of the clamping hook 8. Although the second cam follower means 53 is provided with a rounded end portion 54 contacting the cam surface 52 and is fixed, e.g. welded, to the main body portion 10, it will be appreciated that the second cam follower means 53 could instead be pivoted to the main body portion 10. In this case the cam follower means 53 would be provided with a substantially flat surface for making face-to-face contact with the cam surface 52.

In operation of the pipe coupling 50 the 95 cam ring 5 is turnable in a counter-clockwise direction (as viewed ing the clamping hooks 8 so that the flange engaging heads 13 are swung outwards from a flange clamping posi- tion (shown in Figure 6) to a flange releasing position (shown in Figure 7). This outwards pivoting motion of each flange engaging head is provided by the axially expanding cam surface 52 contacting the cam follower means 53 and pivoting the clamping hook 8 about the pivot 15. On turning the cam ring 5 back in a clockwise direction to its original position, each radially varying cam surface 51 acts on its associated cam follower means 11 to pivot each clamping hook in a clockwise direction (as viewed in Figure 7) to swing the flange engaging heads inwards into flange clamping positions. The cam ring 5 may be turned manually with the aid of handle 56. Alternatively or in addition power means (not shown), e.g. hydraulically operated, may be provided for turning the cam ring. A number, e.g. three, of fixed guides 55 may be provided for guiding the flange of a pipe (not shown) during place- ment against, or removal from, a position adjacent the flange sealing face 3.

It will be appreciated that it is particularly advantageous, especially when applying clamping pressure to a pipe flange to be connected to a pipe coupling, to have substantially faceto-face contact between the cam surface of the cam ring and the cam follower means. If the cam follower means 11 is not pivoted to the main body 10 of the clamping hook 8, it is necessary for the contacting cam surface of the cam ring to follow a complex contour--see, for example, the cam surface provided by blocks 54 in EP-A-0092327-to ensure faceto-face contact as the clamping hook is pivoted on turning of the cam ring. However, by providing a cam follower means 11 which is pivoted to the maim body portion 10 of the clamping hook, the contacting cam surface of the cam ring 5 can be designed to have a cylindrical or other surface formed by movement around the axis 4 of a straight line disposed parallel to, or at a constant angle relative to, the axis 4. Such a cam surface is relatively easy to machine compared with the more complex contour required for the cam surfaces of the cam ring of the pipe coupling described in EP-A-0092327.

With a pipe coupling according to the invention it is necessary to provide at least two clamping means for clamping the flange 21 to the apertured flange sealing face. Preferably each clamping means comprises a movably mounted clamping hook. However, it would be possible, at least in theory, to design a pipe coupling according to the invention having only one movably mounted clamping hook and at least one fixed clamping means. In this case the or each fixed clamping means may comprise, for example, a clamp part fixed relative to the apertured flange sealing face and provided with a wedging surface. The or each wedging surface would act on the flange 21, to urge the latter towards the apertured flange sealing face, when the flange 21 was urged against the wedging surface(s).

Claims

1. A pipe coupling having an axis, an apertured flange sealing face extending transversely of the axis, at least one movably mounted clamping hook comprising a main body portion and a cam follower means, and a turnable cam ring having camming surface means engageable with said cam follower means for moving the clamping hook(s), characterised in that the or at least one of the cam follower means is pivotally connected to its associated main body portion.

2. A pipe coupling according to claim 1, in which the cam ring is mounted for turning movement through an angle of less than 360'1n, where n is the number of movably mounted clamping hooks.

3. A pipe coupling according to claim 1 or 2, having more than one movably mounted clamping hook each provided with a pivotally connected cam follower means engageable with said camming surface means.

4. A pipe coupling according to claim 3, in which the camming surface means comprises a separate cam means for each movable cam follower means.

5. A pipe coupling according to any of the preceding claims, in which the camming sur- face means makes face-to-face contact with GB2164404A 5 the or each cam follower means.

6. A pipe coupling according to any of the preceding claims, in which the or each pivoted cam follower means and the associated camming surface means are slidably keyed together.

7. A pipe coupling according to claim 6, in which one of the keyed together parts comprises a cam slot and the other of the keyed together parts 'comprises an interengaged part captively slidably received in the cam slot.

8. A pipe coupling according to any of claims 1 to 5, in which the or each cam follower means is resiliently urged against the camming surface means.

9. A pipe coupling according to claim 8, comprising spring means for resiliently urging the or each cam follower means against the camming surface means.

10. A pipe coupling constructed and arranged substantially as herein described with reference to, and as illustrated in, Figures 6 and 7 of the accompanying drawings.

Printed in the United Kingdom for Her Majesty's Stationery Office, Dd 8818935, 1986, 4235. Published at The Patent Office, 25 Southampton Buildings, London, WC2A 1 AY, from which copies may be obtained.