CA1077084A - Pipe coupling - Google Patents
Pipe couplingInfo
- Publication number
- CA1077084A CA1077084A CA258,841A CA258841A CA1077084A CA 1077084 A CA1077084 A CA 1077084A CA 258841 A CA258841 A CA 258841A CA 1077084 A CA1077084 A CA 1077084A
- Authority
- CA
- Canada
- Prior art keywords
- pipe
- annular
- coupling body
- coupling
- radially
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Joints With Pressure Members (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A compression coupling having a compression sleeve arranged between a coupling body and a clamping nut. The end of the compression sleeve adjacent the clamping nut is formed with axially extending slots so that it may be radially compressed in the same manner as a collet onto a pipe inserted into the coupling by tightening the clamping nut. The other end of the compression sleeve is formed with an annular projection received in a recess in the end of the coupling body and compresses an annular resilient packing arranged within the recess to establish a seal with the inserted pipe when the clamping nut is tightened.
A compression coupling having a compression sleeve arranged between a coupling body and a clamping nut. The end of the compression sleeve adjacent the clamping nut is formed with axially extending slots so that it may be radially compressed in the same manner as a collet onto a pipe inserted into the coupling by tightening the clamping nut. The other end of the compression sleeve is formed with an annular projection received in a recess in the end of the coupling body and compresses an annular resilient packing arranged within the recess to establish a seal with the inserted pipe when the clamping nut is tightened.
Description
~0770 8 ~ !
The present invention relates to a compression coupling.
In a conventional compression coupling, a compression sleeve is radially compressed by being axially clamped between tapered surfaces on a coupling body in a clamping unit to grip and seal against a pipe. If torque is not applied uniformly to the clamping nut, a part of the compression sleeve may be stressed abruptly causing it to break and making it impossible to provide a proper joint with the pipe. Further, since the rigidity of the compression sleeve in the radial direction is large, a large clamping torque is required to form a seal. A
further disadvantage of such couplings is that they cannot be used if the pipe diameter differs from the rated diameter by more than 0.3 mm.
With a view to mitigating at least some of the above disadvantages, the present invention provides a pipe coupling for connection to a pipe, comprising a coupling body having an inner bore for receiving the end of the pipe, an annular recess surrounding the end of the bore fromwhich the pipe is to be inserted, an annular packing located in said recess, a clamping nut screw threaded onto the end of the coupling body from which the pipe is to be inserted, a flange extending radially inwardly from the end of the nut remote from the coupling body and having a conical radially inner surface flared towards the coupling body, and a compression sleeve operative to surround and grip the pipe and arranged radially within the nut and axially between the flange and the coupling body, the compression sleeve comprising an annular end portion extending into the said recess for compressing the said packing into sealing contact with the pipe, a portion of small radial thickness adjacent the said annular portion and a gripping portion having a radially outer surface tapering away from a ~ .
- 1 - ~ -portion of small radial thickness and engaged by the conical surface of the flange and slots extending axially therethrough and terminating adjacent said portion of small radial thickness, teeth being provided on the radially inner surface of the gripping portion for gripping the pipe, tightening of the nut on the coupling body being operative to radially compress the gripping portion so as to grip the pipe and to displace the compression sleeve axially towards the coupling body whereby to compress the said packing.
The invention will now be described further, by way of example, with reference to the accompanying drawings, in which:
Fig. 1 is a longitudinally sectional view of one embodiment of the present invention, Fig. 2 shows a section of the compression sleeve of the embodiment illustrated in Fig. 1, Fig. 3 is an end view of the compression sleeve of the embodiment shown in Fig. 1, Fig. 4 is a longitudinally sectional view of a second embodiment of the present invention, Fig. 5 is a partially sectioned view of the compression sleeve of the embodiment illustrated in Fig. 4, and Fig. 6 is an end view of the compression sleeve of the embodiment shown in Fig. 4.
Referring to Fig. 1, a pipe coupling of the present invention comprises a coupling body 1 in the form of a nipple, of a cylindrical form including external screw threads 20 and 20' at both its respective axial ends and having a substantially central nut portion 21 and a stepped inner bore. An annular recess 16 is formed on the inner circumference of one end face of the body 1. A clamping nut 2 having a flange portion 17, engages the screw thread 20' on the same side of the body 1 as the recess 16. A compression sleeve 3 is located within the 107708~
clamping nut 2 to support a pipe 5, and an elastic packing 4, such as an O-ring or a square section ring, is located in an annular space 19 defined by the recess 16, the pipe 5 and an end face 6 of an annular portion 22 projecting from the left hand end of the sleeve 3 (as viewed).
The radially inner surface of the flange portion 17 of the clamping nut 2 has an inwardly flared conical face 7 and when the nut 2 is tightened in the body 1, the flange portion 17 presses the compression sleeve 3 both axially and radially.
Referring to Figs. 2 and 3, in the compression sleeve 3, a thin portion 12 is produced by forming a first annular groove 9 on the outer circumferential face and a second annular groove 23 on the inner circumferential face of the body 1 at a position near to the annular portion 22. A pipe gripping portion 14 is formed to extend from this thin portion 12 outwardly in the axial direction, and on the outer circumferen-tial face of this pipe gripping portion 14, a conically tapering face 8 mating with the face 7 on the flange 17. On the radially inner face of the pipe gripping portion 14, there is formed a sharp toothed portion 18, the sharp teeth being defined by a plurality of continuous annular grooves of arcuate section 13.
Further, axial slots 11 (4 slots being present in the embodiment shown in the Figs. 1 to 3) are formed on the pipe supporting portion 14. The slots 11 extend axially from the end face 15 to the vicinity of the thin annular portion 12.
The annular portion 22 has an outer diameter a little smaller than the inner diameter of the annular recess 16. When the body 1 and the nut 2 are tightened together, first the gripping portion 14 is tightened on the pipe 5 in a manner analogous to a collet, then the annular portion 22 moves relative to the cylindrical face of the recess groove 16 towards the left in the drawings so as to compress the packing 4.
In Figs. 4, 5 and 6, another embodiment of the present invention is shown. The coupling of this embodiment further has slots 10 connected to the axially extending slots 11 and extending in the circumferential direction in the thin portion In a coupling of the invention, leakage of fluid from the pipe is prevented by the elastic packing 4. Further, since the sleeve 3 which is interposed between the nut 2 and the pipe 5 has slots 11 and a thin portion 12, there is res-ilience in the sleeve so that the pipe joint has an improvedresistance against shocks or vibrations caused by pressure in the pipe. The elasticity of the pipe gripping portion 14 in the radial direction is much higher than in a pipe joint where no thin portion 12 is provided, and consequently, the pipe coupling can be assembled using a low torque to pipes 5 and the deviation of the outer diameter of the pipe 5 fromthe rated diameter may exceed 0.3 mm.
When the pipe gripping portion 14 of the sleeve 3 is clamped in the radial direction by the nut 2, a deformation in the radial direction is caused in the thin portion 12, and since this deformation is larger than the deformation caused in the pipe gripping portion 14, the clamping force of the pipe gripping portion 14 on the pipe is uniformly distributed over the length of the portion 14. Additionally, since the tooth portion 18 thrust into the pipe 5 is composed of arcuate grooves 13, the teeth 18 are strong and difficult to break.
In particular, such teeth can withstand repeated stresses caused by shocks and vibrations, and can provide a strong grip with appreciation of a relatively low torque. Because of the radial clearance of the annular portion 22 in the recess 16, if the compression sleeve 3 is moved to the right (as viewed) in the axial direction, together with the pipe 5, by the pressure ` :1077084 of the fluid, the fluid escapes through the said radial clearance to relieve the pressure without permanent damage to the coupling.
The embodiment of Figs. 4, 5 and 6, offers the additional advantage that the clamping torque can easily be changed by changing the circumferential dimension of the slots 10.
..
. . .
~: .,"
The present invention relates to a compression coupling.
In a conventional compression coupling, a compression sleeve is radially compressed by being axially clamped between tapered surfaces on a coupling body in a clamping unit to grip and seal against a pipe. If torque is not applied uniformly to the clamping nut, a part of the compression sleeve may be stressed abruptly causing it to break and making it impossible to provide a proper joint with the pipe. Further, since the rigidity of the compression sleeve in the radial direction is large, a large clamping torque is required to form a seal. A
further disadvantage of such couplings is that they cannot be used if the pipe diameter differs from the rated diameter by more than 0.3 mm.
With a view to mitigating at least some of the above disadvantages, the present invention provides a pipe coupling for connection to a pipe, comprising a coupling body having an inner bore for receiving the end of the pipe, an annular recess surrounding the end of the bore fromwhich the pipe is to be inserted, an annular packing located in said recess, a clamping nut screw threaded onto the end of the coupling body from which the pipe is to be inserted, a flange extending radially inwardly from the end of the nut remote from the coupling body and having a conical radially inner surface flared towards the coupling body, and a compression sleeve operative to surround and grip the pipe and arranged radially within the nut and axially between the flange and the coupling body, the compression sleeve comprising an annular end portion extending into the said recess for compressing the said packing into sealing contact with the pipe, a portion of small radial thickness adjacent the said annular portion and a gripping portion having a radially outer surface tapering away from a ~ .
- 1 - ~ -portion of small radial thickness and engaged by the conical surface of the flange and slots extending axially therethrough and terminating adjacent said portion of small radial thickness, teeth being provided on the radially inner surface of the gripping portion for gripping the pipe, tightening of the nut on the coupling body being operative to radially compress the gripping portion so as to grip the pipe and to displace the compression sleeve axially towards the coupling body whereby to compress the said packing.
The invention will now be described further, by way of example, with reference to the accompanying drawings, in which:
Fig. 1 is a longitudinally sectional view of one embodiment of the present invention, Fig. 2 shows a section of the compression sleeve of the embodiment illustrated in Fig. 1, Fig. 3 is an end view of the compression sleeve of the embodiment shown in Fig. 1, Fig. 4 is a longitudinally sectional view of a second embodiment of the present invention, Fig. 5 is a partially sectioned view of the compression sleeve of the embodiment illustrated in Fig. 4, and Fig. 6 is an end view of the compression sleeve of the embodiment shown in Fig. 4.
Referring to Fig. 1, a pipe coupling of the present invention comprises a coupling body 1 in the form of a nipple, of a cylindrical form including external screw threads 20 and 20' at both its respective axial ends and having a substantially central nut portion 21 and a stepped inner bore. An annular recess 16 is formed on the inner circumference of one end face of the body 1. A clamping nut 2 having a flange portion 17, engages the screw thread 20' on the same side of the body 1 as the recess 16. A compression sleeve 3 is located within the 107708~
clamping nut 2 to support a pipe 5, and an elastic packing 4, such as an O-ring or a square section ring, is located in an annular space 19 defined by the recess 16, the pipe 5 and an end face 6 of an annular portion 22 projecting from the left hand end of the sleeve 3 (as viewed).
The radially inner surface of the flange portion 17 of the clamping nut 2 has an inwardly flared conical face 7 and when the nut 2 is tightened in the body 1, the flange portion 17 presses the compression sleeve 3 both axially and radially.
Referring to Figs. 2 and 3, in the compression sleeve 3, a thin portion 12 is produced by forming a first annular groove 9 on the outer circumferential face and a second annular groove 23 on the inner circumferential face of the body 1 at a position near to the annular portion 22. A pipe gripping portion 14 is formed to extend from this thin portion 12 outwardly in the axial direction, and on the outer circumferen-tial face of this pipe gripping portion 14, a conically tapering face 8 mating with the face 7 on the flange 17. On the radially inner face of the pipe gripping portion 14, there is formed a sharp toothed portion 18, the sharp teeth being defined by a plurality of continuous annular grooves of arcuate section 13.
Further, axial slots 11 (4 slots being present in the embodiment shown in the Figs. 1 to 3) are formed on the pipe supporting portion 14. The slots 11 extend axially from the end face 15 to the vicinity of the thin annular portion 12.
The annular portion 22 has an outer diameter a little smaller than the inner diameter of the annular recess 16. When the body 1 and the nut 2 are tightened together, first the gripping portion 14 is tightened on the pipe 5 in a manner analogous to a collet, then the annular portion 22 moves relative to the cylindrical face of the recess groove 16 towards the left in the drawings so as to compress the packing 4.
In Figs. 4, 5 and 6, another embodiment of the present invention is shown. The coupling of this embodiment further has slots 10 connected to the axially extending slots 11 and extending in the circumferential direction in the thin portion In a coupling of the invention, leakage of fluid from the pipe is prevented by the elastic packing 4. Further, since the sleeve 3 which is interposed between the nut 2 and the pipe 5 has slots 11 and a thin portion 12, there is res-ilience in the sleeve so that the pipe joint has an improvedresistance against shocks or vibrations caused by pressure in the pipe. The elasticity of the pipe gripping portion 14 in the radial direction is much higher than in a pipe joint where no thin portion 12 is provided, and consequently, the pipe coupling can be assembled using a low torque to pipes 5 and the deviation of the outer diameter of the pipe 5 fromthe rated diameter may exceed 0.3 mm.
When the pipe gripping portion 14 of the sleeve 3 is clamped in the radial direction by the nut 2, a deformation in the radial direction is caused in the thin portion 12, and since this deformation is larger than the deformation caused in the pipe gripping portion 14, the clamping force of the pipe gripping portion 14 on the pipe is uniformly distributed over the length of the portion 14. Additionally, since the tooth portion 18 thrust into the pipe 5 is composed of arcuate grooves 13, the teeth 18 are strong and difficult to break.
In particular, such teeth can withstand repeated stresses caused by shocks and vibrations, and can provide a strong grip with appreciation of a relatively low torque. Because of the radial clearance of the annular portion 22 in the recess 16, if the compression sleeve 3 is moved to the right (as viewed) in the axial direction, together with the pipe 5, by the pressure ` :1077084 of the fluid, the fluid escapes through the said radial clearance to relieve the pressure without permanent damage to the coupling.
The embodiment of Figs. 4, 5 and 6, offers the additional advantage that the clamping torque can easily be changed by changing the circumferential dimension of the slots 10.
..
. . .
~: .,"
Claims (2)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A pipe coupling for connection to a pipe, compris-ing a coupling body having an inner bore for receiving the end of the pipe, an annular recess surrounding the end of the bore from which the pipe is to be inserted, an annular packing located in said recess, a clamping nut screw threaded onto the end of the coupling body from which the pipe is to be inserted, a flange extending radially inwardly from the end of the nut remote from the coupling body and having a conical radially inner surface flared towards the coupling body, and a compression sleeve oper-ative to surround and grip the pipe and arranged radially within the nut and axially between the flange and the coupling body, the compression sleeve comprising an annular end portion extending into sealing contact with the pipe, a portion of small radial thickness adjacent the said annular portion comprising a first annular groove on the outer circumferential face and a second annular groove on the inner circumferential face of said sleeve, and a gripping portion having a radially outer surface tapering away from the portion of small radial thickness and engaged by the conical surface of the flange and slots extending axially therethrough and terminating adjacent said portion of small radial thickness, teeth being defined by a plurality of continu-ous annular grooves of arcuate section and provided on the radially inner surface of the gripping portion for gripping the pipe, tightening of the nut on the coupling body being operative to radially compress the gripping portion so as to grip the pipe and to displace the compression sleeve axially towards the coupl-ing body whereby to compress the said packing.
2. A compression coupling as claimed in claim 1 in which additional circumferentially extending slots are formed in the portion of small radial thickness each circumferentially ex-tending slot being connected to an axially extending slot.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA258,841A CA1077084A (en) | 1976-08-10 | 1976-08-10 | Pipe coupling |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA258,841A CA1077084A (en) | 1976-08-10 | 1976-08-10 | Pipe coupling |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1077084A true CA1077084A (en) | 1980-05-06 |
Family
ID=4106626
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA258,841A Expired CA1077084A (en) | 1976-08-10 | 1976-08-10 | Pipe coupling |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1077084A (en) |
-
1976
- 1976-08-10 CA CA258,841A patent/CA1077084A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |