CA1043992A - Method of planting ring elements on inner walls of pipes or pipe joints - Google Patents
Method of planting ring elements on inner walls of pipes or pipe jointsInfo
- Publication number
- CA1043992A CA1043992A CA241,013A CA241013A CA1043992A CA 1043992 A CA1043992 A CA 1043992A CA 241013 A CA241013 A CA 241013A CA 1043992 A CA1043992 A CA 1043992A
- Authority
- CA
- Canada
- Prior art keywords
- ring element
- pipe
- blockade
- ring
- diameter
- 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
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L47/00—Connecting arrangements or other fittings specially adapted to be made of plastics or to be used with pipes made of plastics
- F16L47/06—Connecting arrangements or other fittings specially adapted to be made of plastics or to be used with pipes made of plastics with sleeve or socket formed by or in the pipe end
- F16L47/08—Connecting arrangements or other fittings specially adapted to be made of plastics or to be used with pipes made of plastics with sleeve or socket formed by or in the pipe end with sealing rings arranged between the outer surface of one pipe end and the inner surface of the sleeve or socket, the sealing rings being placed previously in the sleeve or socket
- F16L47/10—Connecting arrangements or other fittings specially adapted to be made of plastics or to be used with pipes made of plastics with sleeve or socket formed by or in the pipe end with sealing rings arranged between the outer surface of one pipe end and the inner surface of the sleeve or socket, the sealing rings being placed previously in the sleeve or socket the sealing rings being maintained in place by additional means
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C57/00—Shaping of tube ends, e.g. flanging, belling or closing; Apparatus therefor, e.g. collapsible mandrels
- B29C57/02—Belling or enlarging, e.g. combined with forming a groove
- B29C57/025—Belling or enlarging, e.g. combined with forming a groove combined with the introduction of a sealing ring, e.g. using the sealing element as forming element
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Shaping Of Tube Ends By Bending Or Straightening (AREA)
- Extrusion Moulding Of Plastics Or The Like (AREA)
Abstract
ABSTRACT
A method and an apparatus for fixing a ring element to the inner wall of a thermoplastic pipe are disclosed.
The invention involves the clamping of the ring element on a cylindrical support member and the combined straightening and radial expansion of the ring element into contact with the inner wall. Previously, or simultaneously, the pipe is radially expanded stepwise to its final diameter, the apparatus including suitable mold portions which can impart the desired shape to the pipe end. One part of the mold portion can include radially expandable blockade means which can impart a portion of the desired shape to the pipe end and which can also be instrumental in the clamping and expansion of the ring element. Use of the invention results in a strengthened pipe end which is sized to mate with the end of a next length of pipe and which has a built-in means for mounting packing or other sealing elements.
A method and an apparatus for fixing a ring element to the inner wall of a thermoplastic pipe are disclosed.
The invention involves the clamping of the ring element on a cylindrical support member and the combined straightening and radial expansion of the ring element into contact with the inner wall. Previously, or simultaneously, the pipe is radially expanded stepwise to its final diameter, the apparatus including suitable mold portions which can impart the desired shape to the pipe end. One part of the mold portion can include radially expandable blockade means which can impart a portion of the desired shape to the pipe end and which can also be instrumental in the clamping and expansion of the ring element. Use of the invention results in a strengthened pipe end which is sized to mate with the end of a next length of pipe and which has a built-in means for mounting packing or other sealing elements.
Description
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SP~CIFICA'rION
This invention relates to pipes or pipe joints made of a thermoplastic material and to a method and apparatus for plant-ing ring elements on inner walls of pipes or pipe joints.
Industrial utility of pipes made of a thermoplastic material can be enhanced by increasing the strength at tubular ends of such pipes. It has been found that when a metal ring is mounted on the cylindrical inner wall at the tubular end portion of such pipe, the strength can be effectively increased. Pipe lines having high strength couplings can be prepared by using pipes having a strength increased by provision of ring elements at tubular end por-tions. Further, these pipes having reinforced tubular ends are effective for associating coupling units of apparatusses. The . structural characteristic providing such industrial advantages is that by planting a ring element rectangularly to the axis of the pipe, the inner wall of the pipe at the ring-planted end can easily be standardized and the resistance to crush deformation can be improved. Further, since inner diameters are desirably standard- ~.
ized, the efficiency of the coupling operation can be enhanced, and pipe lines including a great number of couplings being excell-ent in the resistance to crush deformation and re-taining a high reliability for a long time can be formed with high efficiency.
When such ring element is disposed on the inner face of the tubular end of a pipe or pipe joint, the strength of the pipe or joint having an enlarged longitudinal section is reinforced even if said section is further enlarged in the radial direction for containing therein a packing ring. When a synthetic resin pipe is radially enlarged at the end thereof, there is generally observ-29 ed a tendency that the thickness of the end portion is reduced cb/ - 1 -.
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and the strength is lowered. Therefore, provision of a ring ele-ment on the tubular end portion is industrially advantageous also for preventing the above undesired tenclency. In an annular space for containing therein a packinq, for which a greates-t expansion of the diameteris required, the re~uction of the thickness is great and the strength is reduced drasticall~. The brea]cdown or cracking of the pipe or pipe joint by concentration of the external force on that portion of the pipe forming the above annular space can be effectively prevented by provision of a ring element on this space.
It is a primary object of the present invention to pro-vide a method for planting cheap ring elements prepared by custom-ary means, on inner walls of tubular`end portions of pipes and pipe joints with high efficiency so as to impart a required strength to the pipes and pipe joints.
Another object of the present invention is to provide a method for planting ring elements on pipes and pipe joints in which planting of ring elements is performed simultaneously with diameter expansion for formation of coupling portions.
Still another object of the present invention is to provide a method for the preparation of pipes and pipe joints in which, when the diameter is enlarged to form an annular space for containing therein a packing ring at the tubular end portion where the diameter is expanded most greatly, a ring element is planted on the circular peripheral wall surrounding this annular space.
Split molds for forming an annular space for contain-ing therein a packing ring by expanding radially the tubular end portion are known in the art and disclosed in, for example, the 29 specification of British Patent No. 1,124,930. In these devices c~/ - 2 -: ,; ~ ' . ~ . . ' ..-, - . .~
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the mold diameter can be made grea-ter or smaller, but ring elements cannot be planted on inner walls of tubular ends by using these devices.
A suf~icient strength cannot be imparted to the tubular end only by fusion-bonding a riny element to the inner wall of a pipe made of a thermoplastic resin. In order to impart an indus-trially advantageous strength, it is not permissible to use a soft material which is greatly expanded and deformed in the radial direction. ~ccordingly, it is required to use an apparatus which can be separated from ring elements after planting thereof and can hold ring elements tightly and strongly in pipes. This appar-atus is further required to have a function-of planting ring elements on cylindrical inner walls so that the ring element-containing plane crosses rectangularly the tubular axis.
In order to provide ring elements at low costs, it is preferred to use means for cutting coil wires into lengths corres-ponding to a desired diameter and welding both the cut ends to form a ring element. The so formed ring elements are distorted rings in which the coil pitch is left. Accordingly, the appara-tus to be used inside the tubular end is required to have a func-tion of modifying the ring so that it comes to have a plane.
It will readily be understood that this modifying action is effective for not only imparting such modifying force but also generating a force of holding tightly the ring element to prevent displacement or deformation of the ring element by a large force applied to couple the inner wall of the pipe with the ring element.
Accordingly, by virtue of this particular function, a variety of ring elements prepared according to various customary means can 29 be similarly used for imparting a sufficient strength to tubular .
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ends.
In order to prevent po~itively reduction of the thickness of the tube wall to which the ring element is attacl~ed and enhance coupliny between the tube wall and rin~ element as much as possible, it has been found indispensable that while the ring element and the corresponding tube wall are pressed to~ether by a high com-pression force, the tube wall should ~ bent along the periphery of the ring element and an annular groove formed on the tube wall should include therein the ring element. If planting is carried out so that the above condition is satisfied, a great industrial advantage is at-tained when the diameter of the pipe is greatly expanded and the thickness of the tube wall is reduced to form - a-space for containing therein a packing ring and the ring element is disposed in this space of the tube wall. More specifically, the end wall of the tube or pipe where the strength is most reduced is reinforced directly and assuredly by the ring element, and a strong joint is formed at the tube end;
When a ring element is planted on t~e annular groove for containing therein a packing, the ring element controls dir-ectly the packing and provides a most preferred sealing action.It is known that when two pipe ends are telescopically combined, the insertion resistance is imposed on the packing, a trouble of rolling-out of the packing from the packing-containing groove is often caused. In the art, it has been an important problem how to prevent this trouble. It has not been known or expected that this difficult problem would easily be solved ~y a very simple arrangement of combining the above ring element with a packing rlng .
29 If the ring element has a height corresponding to at cbj 4 _ '. ' ' ' ' :. ' .
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least about 1/2 of the depth of the annular groove for contain-ing the ring el~men-t therein, the ring element is allowed to have a sufficient effect of controlling t~e position of the pack-ing ring appropriately. In this arrangement, the pac~.ing ring is disposed on both the sides of the tube axis and is divided into an inner rim part and an outer rim part with an intermcdiate part bridging the ring element disposed betw~en the outer and inner parts. Namely, a groove is formed on the outer peripl~ery of the packing and the ring element is disposed in this groove.
The insertion resistance of the coupling portion contracts these intermediate part and outer rim part and the packing-constituting elastic material which has been rendered hard by this contraction is prevented from passing through between the ring element and the outer periphery of the pipe being inserted. In this state, the inner rim part of the packing is elongated in the axial direction while having contact with the pipe in the pipe-inserting direction, Since the force of elongating the inner rim part of the packing deformed simply in the axial direction by the friction force received from the pipe is smaller than the self-contracting force caused by the large compressive force of the ring element imposed in the radial direction. Accordingly, this elongating force does not move the outer rim part of the packing beyond the ring element, and therefore, the packing can be arranged correctly at the prescribed position. As illustrated above, according to the method of the present invention, a ring element capable of performing the above-mentioned action of controlling the position of the packing ring can be planted on the tube end of a pipe and a strength can be imparted to the tube end of the pipe.
29 The ring element capable of thus reinforcing particularly cb~ ~ 5 . : , ;.~.
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the tube en~ por~ion where the wall tllickness is especially reduced and preventing rolling-out of the packing at the step of coupling the packing with the pipe is planted on the inner wall of the pipe while the cylindrical shape of tlle inner peri-phery of the riny element and the inner diameter ther~of are standardized during this process of planting the ring element on the inner wall of the tube end of the pipe. ~ ring elernent haviny an outer diameter larger than the inner diameter of the pipe is used. In the tubular end portion of the pipe, it is locally heated and softened at an area ranging from the end point to the position where the ring element is planted. Then, the ring element is relatively moved to the planting position while expanding the softened area of the pipe in the radial dir-ection. Subsequently, the expanded softened area of the pipe is contracted by an outer molding membex disposed on the outer periphery of the pipe to bond the ring element tightly to the tu~e wall. In the tube wall of the softened, radially expanded and tightly contracted area, a latent strain causing distortion at the tube end can be removed and in this state, the area is solidified. Therefore, accordin~- to the present invention, tube ends excellent in the uniformity of the shape and diameter can be prepared with high efficiency.
The present invention will be apparent from the accom-panying drawings which show one embodiment of the present inven-tion. This embodiment by no means limits the scope of the present invention, and the present invention includes various modifications made according to need.
In the accompanying drawings, Figure 1 is a partially 29 sectional view of a tube end prepared by planting a ring element cb~ - 6 -, -`. - : ~ ' : , ':.
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on the tube wall forming an annular space for containing therein a packin~ ring.
Figure 2 is a secti~nal view of an inner assembly for preparing the tube end shown in Figure 1.
Figure 3 sho~s a section, taken alon~ the line ~-A, in Figure 2, of a slidinq annular member for applying a pressure to the ring element placed on the inner assembly in the axial direction.
Figure 4 shows the section, taken along the line A-~, in Figure 2, o~ a supporting member combining therewith the sliding annular member shown in Figure 3 so that it can move in the axial direction.
Figure 5 shows the section, taken along the line A-~, in Figure 2, of another sIiding annular member for applying a pressure to the ring element in either the axial direction or the radial direction.
Figure 6 shows the section, taken along the line A-~, in Figure 2, of another supporting member for combining there-with the sliding annular member shown in Figure 5 so that it can move in the axial direction.
Figure 7 is a plan view showing the distortion on the ring element.
Figure ~ is a side view showing the distortion on the ring element.
Figure 9 is a sectional view showing an inner assembl~
in the apparatus where a pressure is applied in both the axial direction and the radial direction of the ring element.
Figure 10 is a sectional view illustratiny the s~age 29 where the outer molding member acts on the inner ~ssembly shown :`' ; '' , :: . ~ : . .
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in Figure 9 which i.5 in the state inserted in the tubular end of the pipe.
Figure 11 is a sectional view showing the stage where the inner assembly and outer molding member are being separated from the tubular end of the pipe.
Fi~ure 12 is a partially sectional view of a modifi-cation of the sliding annular member in which the ring element-adjusting function is further improved.
Figure 13 is an enlarged perspective view showing the relation between the annular member and supporting members having sections shown in Figures 3 and 4, respectively.
Figure 14 is an enlarged perspective view showing the relation between the members shown in Figures S and 6.
Figure 15 is an axially broken section of another inner assembly in a state of contraction in which means for correcting circularity and planeness of the ring element is provided with the split blockade, Figure 16 shows a state of expansion of t~e inner assem-bly shown in Figure 15.
The p~esent invention will now be described in detail with respect to the method for planting ring elements having a high industrial utility on peripheral walls of annular spaces for containing therein a packing ring which are formed on joints formed by expanding tubular ends of pip25, by reference to the accompanying drawings.
According to the method of the present invention, the step of forming such joints, the step of forming annular spaces for receiving therein a packing ring and the step of planting 29 ring elements on such annular spaces can be performed in succession, .
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substanti~lly simultaneously. In other words, according to the present invention, these three steps need not be conducted sep-arately but they can be performed in a continuous manner at sub--stantially on stage.
A supporting member 10 for placiny thereon a ring ele-ment is disposed to support the ring element annularly. One specific ins-tance of such supporting member is a cylindrical block.
A split blockade 9 is combined with this cylindrical block so that their axes are in agreement with each other. This split blockade 9 is formed by arranging radially split movable pieces in a disc-like form by means of a spring ring 12. Movable pieces 9a gather-ed in a disc~like form are tapered toward the center, and the expan-sion or contraction of the blockade 9 in the radial direction is performed by the reciprocating movement of thrust taper rings 8 cooperable with the tapered parts of the movable pieces. A slid-ing annular member 11 capable of moving in the axial direction toward the blockade 9 is assembled on the cylindrical block of the supporting member 10. A ring element 5 is hung on the support-ing member 10 is prevented from moving on the supporting member 10 by expanding the split blockade 9 in the radial direction. In this state, the annular member ll is moved in the axial direction toward the ring element 5 so that the ring element 5 can be tightly gripped between the annular member ll and the blockade 9.
The tubular end of a pipe 1 shown in Figure 1, includes a first expanded diameter portion 2 for receiving therein the tubular end of another pipe l', a second expanded diameter portion 3 for receiving therein a packing ring, which has a larger dia-meter than the ~irst expanded diameter portion 2, and the ring 29 element 5. The above-mentioned assembly is arranged, as shown cb/
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; in Figure 2, for formin~ such pipe s~ruct~lr~. More specifically, the peripheral shapes of the split blockade 9 and the annular member ll are arranged to forrn an annular space for r~ceiving therein a packing ring ~hen they are com~ined. ~ mol~ 7 for forming the first expanded diameter portion 2 is combined with the blockade 9 so that their axes are in agreement with each other.
When the split blockade 9 is contracted, i-ts diameter is smaller than the outer diameter of the mold 7and when the blockade 9 is expanded, its diameter is larger than the outer diameter of the mold 7. By assembling the mold 7, split blockade 3 and annular member 11 in the foregoing manner, the tubular end having a shape shown in Figure l is formed by one step.
The assembly to be used in the interior of the pipe, which is shown in Figure 2, has the following structure.
In case ring elements 5 are prepared at low costs and have a-great distortion, it is necessary to enhance the circularity and planeness in the ring elements by correction. In the assembly shown in Figure 2, the correcting function o~ enhancing the circular-ity and planeness to prescribed levels is particularly increased.
More specifically, the supporting member lO including a cylindrical block is formed to have a peculiar shape at the part adjoining the blockade 9, so that it comes to have a section shown in Figure 4 or 5. In the arrangement shown in Figure 4, four projections 20 are disposed around the -supporting member lO. A distorted ring element S is placed on the projections 20. Pick-up small diameter portions 17 are annularly formed on the top end of the annular member ll are formed so that the small diameter portions 12 can intrude between the adjoining two projections 20 from the axial 29 direction (see Figure 3~. Each pick-up small diameter portion 17 cbj~ - 10 -..... ... . .. .
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has on the top e~d ther~of a tapered face 26 inclin~d in the a~ial dlrection. The assembling arrangemel~-t of these members are illustrated in Figure 13.
In the above arrangement, when the annular member 10 is slided in the axial direction to cause respective pick-up small diameter portions 17 to intrude between adjoining projections 20, the tapered end faces 26 are directed ~o the inner face of the distorted ring element such as shown in Figures 7 and 8 and the inner face is expanded along the tapered faces 26. In this manner, the small diameter portions 17 pick up the ring element 5 and advance toward the projections 20 to form a complete cylindrical face. The inner face of the ring 5 is corrected by the thus assembled cylindrical face so that it comes to have a required circularity. The annular member 11 grips and presses the ring 5 to the blockade 9 through a peripheral wall 28. Thus, the distor-tion of the ring 5 with respect to the planeness is thus corrected and the ring 5 is tightly held in the state crossing rectangularly the axis of the assembly.
In the arrangement shown in Figure 5, a small diamèter 20 portion 17 forming a com21etely cylindrical face 18 is provided at the top end of the annular member 11 so that a pressing peri-pheral wall 28 is formed. The small diameter portion 17 has on the top end thereof a taper 26 of a conical face.
In the supporting member shown in Figure 6, an annular projection 20 is provided. The inner face of the cylindrical small diameter portion 17 has a size sufficient to receive the annular projection 20 on the inner face of the small diameter por-tion 17. The assembling arrangement of these members is illus-29 trated in Figure 14. A distorted ring element 5 is placed in the cb/
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distorted st~te on the outer periplleral face 21 of the annular projection 20 h~ving a diameter smaller than the diameter of the ring element 5, and as the annular taper 26 is brought near, the ring element 5 is pressed to th~ blockade 9. The taper 26 is caused to intrude into the inner face of the ~locked ring ele-ment 5 and the diameter of the ring element 5 is expanded so that a desired circulari-ty is attained in tlle ring element S.
At this point, the annular taper 26 intrudes into an annular concavity formed on the peripheral face of the split blockade 9 as shown in Figure 12, and the ring 5 is expanded and corrected sufficiently by the cylindrlcal face 18 of the annular small diameter portion 17. The correction ofthe ring 5 in respect to the planeness is accomplished by pressing the ring between the pressing peripheral wall 28 and the blockade 9.
A cylindrical space 22 shown in Figures 3 and 5 is formed for receiving therein the cylindrical block of the support-ing member 10 and a cylindrical space 23 shown in Figures 4 and 6 is formed for containing therein the thrust taper ring 8. The thrust taper ring 8 for changing the diameter of the bloc~ade 9 is precisely guided by a shaft member 8' inserted therethrough.
This shaft member 8' combines the mold 7 with tile supporting member 10. The thrust taper ring 8 has a rod 15a extending in the axial direction outwardly of the supporting member 10/ and the thrust taper ring 8 is operated by this rod 15a. A rod 16 is also attached to the supporting member 10. Further, an indep-endent rod 14a is attached to the annular member 11. These rods are used as fluid driven rods or solenoid driven rods for moving the related members freely in the axial direction.
29 The inner assembly is constructed, as shown in Figure 9, cb/ - 12 -.. . . .
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so that the rincJ elernent 5 is presse~ under such a pressing force as will correct the distortion on the ring element 5. Then, the pipe 1 is locally heated irl a prescribed zone ranging from the tubular end to the ring elem~nt-p]an-ting position. In this embodiment, the zone extending up to tlle first large diameter -~ portion 2 is heated for softening and deformation. The softened terminal zone of the pipe 1 is inserted into the above assembly, and the diameter is expanded by the mold 7 for forming the first large diameter portion 2 and then by the blockade 3. The softened zone and the assembly are brought close to each other until the softened zone goes across the ring element 5 and arrives at a pres-cribed position on the annular member 11. The basic movement is one of advancing the entire assembly by the rod 16 and insertiny it into the softened zone of the fixed pipe. The tubular end which has gone across the ring S is expanded so that the diameter is made equal to the outer diameter of the ring. A molding cavity of the outer molding member ~9 presses the thus expanded tubular end at the position corresponding to the ring 5, and the wall of the tubular end is bent along the outer periphery of the ring 5 to form a groove on the tube wall and the ring 5 is pressed into this groove. This state is illustrated in Figure 10. The molding cavity of the outer molding member 29 is formed so that a desired shape is molded on completion of the planting operation. In this embodiment, a groove cavity is formed in the outer molding member 29 so that a groove capable of bonding the ring 5 most tightly to the tube wall is formed on the tube wall. When the required strength is not so high andit is sufficient that the outer peri-pheral face of the ring is caved in the tubular wall, the molding 29 cavity may be formed to have a simple cylindrical face so that c~ 13 -. - . , .
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the tu~ular end has a plane face on the periphery thereof on completion of the ring planting operation.
The ring element S is caused to go across the sof~ened zone without being distortea and is fixed to the inner wall o~ the pipe precisely at the annular position de~ined by the assembly placed in the pipe. l'he softened zone is cooled and the outer molding member 29 is moved in the radial direction to further contract the split blockade 9. This operation is accomplished by moving the thrust taper ring 8 upwardly in the left in Figure 11 by means of the rod 15a. When the blockade 9 is contracted until its diameter is made smaller than the inner diameter of the ring 5, the entire assembly is taken out from the tubular end in the axial direction without being hindered by this ring. In the foregoing manner, the ring element is attached to the tube wall at a portion that is expanded most broadly and is most weakened, whereby the weak portion of the tube end is effectively reinforced.
In addition, if a packing ring naving a groove corresponding to the ring element is combined with this ring element, t'ne difficult problem of preventing rolling of the packing can be successfully solved.
As is seen from the foregoing embodiment, an ordinary distortion of the ring element can be corrected by cooperation of the annular member 11 and the split blockade 9. ~ing elements having a much greater distortion than that shown in Figures 7 and 8, for example, ring elements having an oval or hear~like shape, can be prepared at much reduced manufacturing costs. Accordingly, i~ the operation of hanging such ring elements on the supporting member is facilitated and their circularity and planeness are 29 corrected assuredly and precisely, industrial advantages will be ~/ - 14 -~ . . - ~, . . :
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further enhanced. Furthermor~, the material and shape of the ring element can be chosen in ~road~r ran~es. In this case, not only metallic hollow rings having an angular section but also hard plastic rings can be used appropriately so as to meet demands.
Any of circular, oval, semicircular, polygonal and trapezoid sectional shapes can be adopted as the sectional shape of the ring element. In tlle present inven~ion, tnere may be adopted the following modification of the a~ove-mentioned assembly for facilitating the operation of hanging the ring element and correct-ing the ring element so as to impart thereto a prescribed shape.
Referring now to Figure 12 which is an enlarged viewof the main structure of the above modification, the taper 26 disposed on the top end of the small diameter portion 17 i5 arranged to project from the supporting member lO into the ad-joining split blockade 9 so that the cylindrical face of the small diameter portion 17 for picking up the ring elements con-fronts the inner peripheral face of the ring element 5. A cyl-indrical face 32 is formed on the thrust taper ring 8 to be used for moving the blockade 9 in the radial direction so that the height of the outer peripheral face of the blockade 9 from the axis is made constant when this outer peripheral face is utilized as a mold. Further, a cylindrical face 34 corresponding to this cylindrical face 32 is formed on the inner peripheral wall of radially split pieces constituting the blockade 9. In other words, since the largest expansion of the split blockade 9 pro-viding the largest diameter is attained when confronting of the tapered portions is released and both the cylindrical faces are caused to confront each other, the length of the outer periphery 29 of the blockade 9 and its height from the axis are always made ~b/ - 15 -:
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constant. In order to facilitate the operation of hanging a ring element 5 havin~ a lar~e distortion on the supporting member 10, the supporting member should be molded to have an outer diameter smaller than a ring diameter narrowed by this distortion (defined by processincJ means for preparing a ring element from a material).
Accordingly, the quantity of correction of the ring element 5 in the radial direction by t~e annular mem~er 11 can be increased and therefore, the length of the top taper 26 of the pick up small diameter portion 17 is increased in proportion to the correction quantity. When the ring element 5 is pressed in the axial direc-tion by the pressing peripheral wall 28 of the annular member 11, the taper 26, the length of which is increased, should be removed outwardly of the inner peripheral face of the ring element 5. On the blockade 9, there is formed an annular recess 35 for locating the lengthened taper 26 when the blockade 9 is maximally expandedO
By this arrangement, when the ring element 5 is pressed in the axial direction, the cylindrical face 18 of the small diameter portion 17 should inevitably confront the inner peripheral face of the ring element 5, whereby the height and position of the ring element 5 can be maintained correctly. When tne ring element is combined with a deeper groove of the tu~ular wall, the ring element is projected outwardly from the blockade 9, the ~iameter of which is maximally expanded. An annular guide 30 having an outward taper is mounted on the blockade 9 to cause the softened zone of the pipe to go beyond the ring element 5 from the outer peripheral face of the blockade 9. This modification ls especially effective when a larger quantity of correction is made on ring elements, it is desired to maintain the height of rings ver~ precisely ox when 29 ring elements are combined with deeper grooves of t~lbular ends.
ck/ - 16 -.- ~ . , ', ! ' ' . ~ .
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,' , '~ ' '" '," ' ,' ' ~ ' ' ' ' ' ., . ' '' . " ' ~' ' " ' ' ' In Figures 15 and 16, the split blockade 9 is modified to provide the means for correcting circularity and planeness of the ring element therewith.
In the modification, a top taper 26' for picking-up a ring element, a small diameter portion (7) for correcting the circularity of a ring element 5 and also a radial wall 28' for compressing a ring element to firm:Ly hold and correct the plane-ness of a ring element are formed on the split blockade 9 at the radial side facing the supporting member 10.
The annular member 11 is then provided a radial face 11' on the top end, thereby to compress the ring element 5 between the radial face ll' and the radial wall 28'. The correcting means provided on the split blockade 9 is arranged in a complete annular state when the split blockade g is expanded, and movable pieces 9a may be contracted having respectively a corresponding part of the correcting means those of which are repeatedly formin~ the complete annular shape in expanded state.
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SP~CIFICA'rION
This invention relates to pipes or pipe joints made of a thermoplastic material and to a method and apparatus for plant-ing ring elements on inner walls of pipes or pipe joints.
Industrial utility of pipes made of a thermoplastic material can be enhanced by increasing the strength at tubular ends of such pipes. It has been found that when a metal ring is mounted on the cylindrical inner wall at the tubular end portion of such pipe, the strength can be effectively increased. Pipe lines having high strength couplings can be prepared by using pipes having a strength increased by provision of ring elements at tubular end por-tions. Further, these pipes having reinforced tubular ends are effective for associating coupling units of apparatusses. The . structural characteristic providing such industrial advantages is that by planting a ring element rectangularly to the axis of the pipe, the inner wall of the pipe at the ring-planted end can easily be standardized and the resistance to crush deformation can be improved. Further, since inner diameters are desirably standard- ~.
ized, the efficiency of the coupling operation can be enhanced, and pipe lines including a great number of couplings being excell-ent in the resistance to crush deformation and re-taining a high reliability for a long time can be formed with high efficiency.
When such ring element is disposed on the inner face of the tubular end of a pipe or pipe joint, the strength of the pipe or joint having an enlarged longitudinal section is reinforced even if said section is further enlarged in the radial direction for containing therein a packing ring. When a synthetic resin pipe is radially enlarged at the end thereof, there is generally observ-29 ed a tendency that the thickness of the end portion is reduced cb/ - 1 -.
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and the strength is lowered. Therefore, provision of a ring ele-ment on the tubular end portion is industrially advantageous also for preventing the above undesired tenclency. In an annular space for containing therein a packinq, for which a greates-t expansion of the diameteris required, the re~uction of the thickness is great and the strength is reduced drasticall~. The brea]cdown or cracking of the pipe or pipe joint by concentration of the external force on that portion of the pipe forming the above annular space can be effectively prevented by provision of a ring element on this space.
It is a primary object of the present invention to pro-vide a method for planting cheap ring elements prepared by custom-ary means, on inner walls of tubular`end portions of pipes and pipe joints with high efficiency so as to impart a required strength to the pipes and pipe joints.
Another object of the present invention is to provide a method for planting ring elements on pipes and pipe joints in which planting of ring elements is performed simultaneously with diameter expansion for formation of coupling portions.
Still another object of the present invention is to provide a method for the preparation of pipes and pipe joints in which, when the diameter is enlarged to form an annular space for containing therein a packing ring at the tubular end portion where the diameter is expanded most greatly, a ring element is planted on the circular peripheral wall surrounding this annular space.
Split molds for forming an annular space for contain-ing therein a packing ring by expanding radially the tubular end portion are known in the art and disclosed in, for example, the 29 specification of British Patent No. 1,124,930. In these devices c~/ - 2 -: ,; ~ ' . ~ . . ' ..-, - . .~
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the mold diameter can be made grea-ter or smaller, but ring elements cannot be planted on inner walls of tubular ends by using these devices.
A suf~icient strength cannot be imparted to the tubular end only by fusion-bonding a riny element to the inner wall of a pipe made of a thermoplastic resin. In order to impart an indus-trially advantageous strength, it is not permissible to use a soft material which is greatly expanded and deformed in the radial direction. ~ccordingly, it is required to use an apparatus which can be separated from ring elements after planting thereof and can hold ring elements tightly and strongly in pipes. This appar-atus is further required to have a function-of planting ring elements on cylindrical inner walls so that the ring element-containing plane crosses rectangularly the tubular axis.
In order to provide ring elements at low costs, it is preferred to use means for cutting coil wires into lengths corres-ponding to a desired diameter and welding both the cut ends to form a ring element. The so formed ring elements are distorted rings in which the coil pitch is left. Accordingly, the appara-tus to be used inside the tubular end is required to have a func-tion of modifying the ring so that it comes to have a plane.
It will readily be understood that this modifying action is effective for not only imparting such modifying force but also generating a force of holding tightly the ring element to prevent displacement or deformation of the ring element by a large force applied to couple the inner wall of the pipe with the ring element.
Accordingly, by virtue of this particular function, a variety of ring elements prepared according to various customary means can 29 be similarly used for imparting a sufficient strength to tubular .
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ends.
In order to prevent po~itively reduction of the thickness of the tube wall to which the ring element is attacl~ed and enhance coupliny between the tube wall and rin~ element as much as possible, it has been found indispensable that while the ring element and the corresponding tube wall are pressed to~ether by a high com-pression force, the tube wall should ~ bent along the periphery of the ring element and an annular groove formed on the tube wall should include therein the ring element. If planting is carried out so that the above condition is satisfied, a great industrial advantage is at-tained when the diameter of the pipe is greatly expanded and the thickness of the tube wall is reduced to form - a-space for containing therein a packing ring and the ring element is disposed in this space of the tube wall. More specifically, the end wall of the tube or pipe where the strength is most reduced is reinforced directly and assuredly by the ring element, and a strong joint is formed at the tube end;
When a ring element is planted on t~e annular groove for containing therein a packing, the ring element controls dir-ectly the packing and provides a most preferred sealing action.It is known that when two pipe ends are telescopically combined, the insertion resistance is imposed on the packing, a trouble of rolling-out of the packing from the packing-containing groove is often caused. In the art, it has been an important problem how to prevent this trouble. It has not been known or expected that this difficult problem would easily be solved ~y a very simple arrangement of combining the above ring element with a packing rlng .
29 If the ring element has a height corresponding to at cbj 4 _ '. ' ' ' ' :. ' .
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least about 1/2 of the depth of the annular groove for contain-ing the ring el~men-t therein, the ring element is allowed to have a sufficient effect of controlling t~e position of the pack-ing ring appropriately. In this arrangement, the pac~.ing ring is disposed on both the sides of the tube axis and is divided into an inner rim part and an outer rim part with an intermcdiate part bridging the ring element disposed betw~en the outer and inner parts. Namely, a groove is formed on the outer peripl~ery of the packing and the ring element is disposed in this groove.
The insertion resistance of the coupling portion contracts these intermediate part and outer rim part and the packing-constituting elastic material which has been rendered hard by this contraction is prevented from passing through between the ring element and the outer periphery of the pipe being inserted. In this state, the inner rim part of the packing is elongated in the axial direction while having contact with the pipe in the pipe-inserting direction, Since the force of elongating the inner rim part of the packing deformed simply in the axial direction by the friction force received from the pipe is smaller than the self-contracting force caused by the large compressive force of the ring element imposed in the radial direction. Accordingly, this elongating force does not move the outer rim part of the packing beyond the ring element, and therefore, the packing can be arranged correctly at the prescribed position. As illustrated above, according to the method of the present invention, a ring element capable of performing the above-mentioned action of controlling the position of the packing ring can be planted on the tube end of a pipe and a strength can be imparted to the tube end of the pipe.
29 The ring element capable of thus reinforcing particularly cb~ ~ 5 . : , ;.~.
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the tube en~ por~ion where the wall tllickness is especially reduced and preventing rolling-out of the packing at the step of coupling the packing with the pipe is planted on the inner wall of the pipe while the cylindrical shape of tlle inner peri-phery of the riny element and the inner diameter ther~of are standardized during this process of planting the ring element on the inner wall of the tube end of the pipe. ~ ring elernent haviny an outer diameter larger than the inner diameter of the pipe is used. In the tubular end portion of the pipe, it is locally heated and softened at an area ranging from the end point to the position where the ring element is planted. Then, the ring element is relatively moved to the planting position while expanding the softened area of the pipe in the radial dir-ection. Subsequently, the expanded softened area of the pipe is contracted by an outer molding membex disposed on the outer periphery of the pipe to bond the ring element tightly to the tu~e wall. In the tube wall of the softened, radially expanded and tightly contracted area, a latent strain causing distortion at the tube end can be removed and in this state, the area is solidified. Therefore, accordin~- to the present invention, tube ends excellent in the uniformity of the shape and diameter can be prepared with high efficiency.
The present invention will be apparent from the accom-panying drawings which show one embodiment of the present inven-tion. This embodiment by no means limits the scope of the present invention, and the present invention includes various modifications made according to need.
In the accompanying drawings, Figure 1 is a partially 29 sectional view of a tube end prepared by planting a ring element cb~ - 6 -, -`. - : ~ ' : , ':.
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on the tube wall forming an annular space for containing therein a packin~ ring.
Figure 2 is a secti~nal view of an inner assembly for preparing the tube end shown in Figure 1.
Figure 3 sho~s a section, taken alon~ the line ~-A, in Figure 2, of a slidinq annular member for applying a pressure to the ring element placed on the inner assembly in the axial direction.
Figure 4 shows the section, taken along the line A-~, in Figure 2, o~ a supporting member combining therewith the sliding annular member shown in Figure 3 so that it can move in the axial direction.
Figure 5 shows the section, taken along the line A-~, in Figure 2, of another sIiding annular member for applying a pressure to the ring element in either the axial direction or the radial direction.
Figure 6 shows the section, taken along the line A-~, in Figure 2, of another supporting member for combining there-with the sliding annular member shown in Figure 5 so that it can move in the axial direction.
Figure 7 is a plan view showing the distortion on the ring element.
Figure ~ is a side view showing the distortion on the ring element.
Figure 9 is a sectional view showing an inner assembl~
in the apparatus where a pressure is applied in both the axial direction and the radial direction of the ring element.
Figure 10 is a sectional view illustratiny the s~age 29 where the outer molding member acts on the inner ~ssembly shown :`' ; '' , :: . ~ : . .
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in Figure 9 which i.5 in the state inserted in the tubular end of the pipe.
Figure 11 is a sectional view showing the stage where the inner assembly and outer molding member are being separated from the tubular end of the pipe.
Fi~ure 12 is a partially sectional view of a modifi-cation of the sliding annular member in which the ring element-adjusting function is further improved.
Figure 13 is an enlarged perspective view showing the relation between the annular member and supporting members having sections shown in Figures 3 and 4, respectively.
Figure 14 is an enlarged perspective view showing the relation between the members shown in Figures S and 6.
Figure 15 is an axially broken section of another inner assembly in a state of contraction in which means for correcting circularity and planeness of the ring element is provided with the split blockade, Figure 16 shows a state of expansion of t~e inner assem-bly shown in Figure 15.
The p~esent invention will now be described in detail with respect to the method for planting ring elements having a high industrial utility on peripheral walls of annular spaces for containing therein a packing ring which are formed on joints formed by expanding tubular ends of pip25, by reference to the accompanying drawings.
According to the method of the present invention, the step of forming such joints, the step of forming annular spaces for receiving therein a packing ring and the step of planting 29 ring elements on such annular spaces can be performed in succession, .
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substanti~lly simultaneously. In other words, according to the present invention, these three steps need not be conducted sep-arately but they can be performed in a continuous manner at sub--stantially on stage.
A supporting member 10 for placiny thereon a ring ele-ment is disposed to support the ring element annularly. One specific ins-tance of such supporting member is a cylindrical block.
A split blockade 9 is combined with this cylindrical block so that their axes are in agreement with each other. This split blockade 9 is formed by arranging radially split movable pieces in a disc-like form by means of a spring ring 12. Movable pieces 9a gather-ed in a disc~like form are tapered toward the center, and the expan-sion or contraction of the blockade 9 in the radial direction is performed by the reciprocating movement of thrust taper rings 8 cooperable with the tapered parts of the movable pieces. A slid-ing annular member 11 capable of moving in the axial direction toward the blockade 9 is assembled on the cylindrical block of the supporting member 10. A ring element 5 is hung on the support-ing member 10 is prevented from moving on the supporting member 10 by expanding the split blockade 9 in the radial direction. In this state, the annular member ll is moved in the axial direction toward the ring element 5 so that the ring element 5 can be tightly gripped between the annular member ll and the blockade 9.
The tubular end of a pipe 1 shown in Figure 1, includes a first expanded diameter portion 2 for receiving therein the tubular end of another pipe l', a second expanded diameter portion 3 for receiving therein a packing ring, which has a larger dia-meter than the ~irst expanded diameter portion 2, and the ring 29 element 5. The above-mentioned assembly is arranged, as shown cb/
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; in Figure 2, for formin~ such pipe s~ruct~lr~. More specifically, the peripheral shapes of the split blockade 9 and the annular member ll are arranged to forrn an annular space for r~ceiving therein a packing ring ~hen they are com~ined. ~ mol~ 7 for forming the first expanded diameter portion 2 is combined with the blockade 9 so that their axes are in agreement with each other.
When the split blockade 9 is contracted, i-ts diameter is smaller than the outer diameter of the mold 7and when the blockade 9 is expanded, its diameter is larger than the outer diameter of the mold 7. By assembling the mold 7, split blockade 3 and annular member 11 in the foregoing manner, the tubular end having a shape shown in Figure l is formed by one step.
The assembly to be used in the interior of the pipe, which is shown in Figure 2, has the following structure.
In case ring elements 5 are prepared at low costs and have a-great distortion, it is necessary to enhance the circularity and planeness in the ring elements by correction. In the assembly shown in Figure 2, the correcting function o~ enhancing the circular-ity and planeness to prescribed levels is particularly increased.
More specifically, the supporting member lO including a cylindrical block is formed to have a peculiar shape at the part adjoining the blockade 9, so that it comes to have a section shown in Figure 4 or 5. In the arrangement shown in Figure 4, four projections 20 are disposed around the -supporting member lO. A distorted ring element S is placed on the projections 20. Pick-up small diameter portions 17 are annularly formed on the top end of the annular member ll are formed so that the small diameter portions 12 can intrude between the adjoining two projections 20 from the axial 29 direction (see Figure 3~. Each pick-up small diameter portion 17 cbj~ - 10 -..... ... . .. .
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has on the top e~d ther~of a tapered face 26 inclin~d in the a~ial dlrection. The assembling arrangemel~-t of these members are illustrated in Figure 13.
In the above arrangement, when the annular member 10 is slided in the axial direction to cause respective pick-up small diameter portions 17 to intrude between adjoining projections 20, the tapered end faces 26 are directed ~o the inner face of the distorted ring element such as shown in Figures 7 and 8 and the inner face is expanded along the tapered faces 26. In this manner, the small diameter portions 17 pick up the ring element 5 and advance toward the projections 20 to form a complete cylindrical face. The inner face of the ring 5 is corrected by the thus assembled cylindrical face so that it comes to have a required circularity. The annular member 11 grips and presses the ring 5 to the blockade 9 through a peripheral wall 28. Thus, the distor-tion of the ring 5 with respect to the planeness is thus corrected and the ring 5 is tightly held in the state crossing rectangularly the axis of the assembly.
In the arrangement shown in Figure 5, a small diamèter 20 portion 17 forming a com21etely cylindrical face 18 is provided at the top end of the annular member 11 so that a pressing peri-pheral wall 28 is formed. The small diameter portion 17 has on the top end thereof a taper 26 of a conical face.
In the supporting member shown in Figure 6, an annular projection 20 is provided. The inner face of the cylindrical small diameter portion 17 has a size sufficient to receive the annular projection 20 on the inner face of the small diameter por-tion 17. The assembling arrangement of these members is illus-29 trated in Figure 14. A distorted ring element 5 is placed in the cb/
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distorted st~te on the outer periplleral face 21 of the annular projection 20 h~ving a diameter smaller than the diameter of the ring element 5, and as the annular taper 26 is brought near, the ring element 5 is pressed to th~ blockade 9. The taper 26 is caused to intrude into the inner face of the ~locked ring ele-ment 5 and the diameter of the ring element 5 is expanded so that a desired circulari-ty is attained in tlle ring element S.
At this point, the annular taper 26 intrudes into an annular concavity formed on the peripheral face of the split blockade 9 as shown in Figure 12, and the ring 5 is expanded and corrected sufficiently by the cylindrlcal face 18 of the annular small diameter portion 17. The correction ofthe ring 5 in respect to the planeness is accomplished by pressing the ring between the pressing peripheral wall 28 and the blockade 9.
A cylindrical space 22 shown in Figures 3 and 5 is formed for receiving therein the cylindrical block of the support-ing member 10 and a cylindrical space 23 shown in Figures 4 and 6 is formed for containing therein the thrust taper ring 8. The thrust taper ring 8 for changing the diameter of the bloc~ade 9 is precisely guided by a shaft member 8' inserted therethrough.
This shaft member 8' combines the mold 7 with tile supporting member 10. The thrust taper ring 8 has a rod 15a extending in the axial direction outwardly of the supporting member 10/ and the thrust taper ring 8 is operated by this rod 15a. A rod 16 is also attached to the supporting member 10. Further, an indep-endent rod 14a is attached to the annular member 11. These rods are used as fluid driven rods or solenoid driven rods for moving the related members freely in the axial direction.
29 The inner assembly is constructed, as shown in Figure 9, cb/ - 12 -.. . . .
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so that the rincJ elernent 5 is presse~ under such a pressing force as will correct the distortion on the ring element 5. Then, the pipe 1 is locally heated irl a prescribed zone ranging from the tubular end to the ring elem~nt-p]an-ting position. In this embodiment, the zone extending up to tlle first large diameter -~ portion 2 is heated for softening and deformation. The softened terminal zone of the pipe 1 is inserted into the above assembly, and the diameter is expanded by the mold 7 for forming the first large diameter portion 2 and then by the blockade 3. The softened zone and the assembly are brought close to each other until the softened zone goes across the ring element 5 and arrives at a pres-cribed position on the annular member 11. The basic movement is one of advancing the entire assembly by the rod 16 and insertiny it into the softened zone of the fixed pipe. The tubular end which has gone across the ring S is expanded so that the diameter is made equal to the outer diameter of the ring. A molding cavity of the outer molding member ~9 presses the thus expanded tubular end at the position corresponding to the ring 5, and the wall of the tubular end is bent along the outer periphery of the ring 5 to form a groove on the tube wall and the ring 5 is pressed into this groove. This state is illustrated in Figure 10. The molding cavity of the outer molding member 29 is formed so that a desired shape is molded on completion of the planting operation. In this embodiment, a groove cavity is formed in the outer molding member 29 so that a groove capable of bonding the ring 5 most tightly to the tube wall is formed on the tube wall. When the required strength is not so high andit is sufficient that the outer peri-pheral face of the ring is caved in the tubular wall, the molding 29 cavity may be formed to have a simple cylindrical face so that c~ 13 -. - . , .
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the tu~ular end has a plane face on the periphery thereof on completion of the ring planting operation.
The ring element S is caused to go across the sof~ened zone without being distortea and is fixed to the inner wall o~ the pipe precisely at the annular position de~ined by the assembly placed in the pipe. l'he softened zone is cooled and the outer molding member 29 is moved in the radial direction to further contract the split blockade 9. This operation is accomplished by moving the thrust taper ring 8 upwardly in the left in Figure 11 by means of the rod 15a. When the blockade 9 is contracted until its diameter is made smaller than the inner diameter of the ring 5, the entire assembly is taken out from the tubular end in the axial direction without being hindered by this ring. In the foregoing manner, the ring element is attached to the tube wall at a portion that is expanded most broadly and is most weakened, whereby the weak portion of the tube end is effectively reinforced.
In addition, if a packing ring naving a groove corresponding to the ring element is combined with this ring element, t'ne difficult problem of preventing rolling of the packing can be successfully solved.
As is seen from the foregoing embodiment, an ordinary distortion of the ring element can be corrected by cooperation of the annular member 11 and the split blockade 9. ~ing elements having a much greater distortion than that shown in Figures 7 and 8, for example, ring elements having an oval or hear~like shape, can be prepared at much reduced manufacturing costs. Accordingly, i~ the operation of hanging such ring elements on the supporting member is facilitated and their circularity and planeness are 29 corrected assuredly and precisely, industrial advantages will be ~/ - 14 -~ . . - ~, . . :
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further enhanced. Furthermor~, the material and shape of the ring element can be chosen in ~road~r ran~es. In this case, not only metallic hollow rings having an angular section but also hard plastic rings can be used appropriately so as to meet demands.
Any of circular, oval, semicircular, polygonal and trapezoid sectional shapes can be adopted as the sectional shape of the ring element. In tlle present inven~ion, tnere may be adopted the following modification of the a~ove-mentioned assembly for facilitating the operation of hanging the ring element and correct-ing the ring element so as to impart thereto a prescribed shape.
Referring now to Figure 12 which is an enlarged viewof the main structure of the above modification, the taper 26 disposed on the top end of the small diameter portion 17 i5 arranged to project from the supporting member lO into the ad-joining split blockade 9 so that the cylindrical face of the small diameter portion 17 for picking up the ring elements con-fronts the inner peripheral face of the ring element 5. A cyl-indrical face 32 is formed on the thrust taper ring 8 to be used for moving the blockade 9 in the radial direction so that the height of the outer peripheral face of the blockade 9 from the axis is made constant when this outer peripheral face is utilized as a mold. Further, a cylindrical face 34 corresponding to this cylindrical face 32 is formed on the inner peripheral wall of radially split pieces constituting the blockade 9. In other words, since the largest expansion of the split blockade 9 pro-viding the largest diameter is attained when confronting of the tapered portions is released and both the cylindrical faces are caused to confront each other, the length of the outer periphery 29 of the blockade 9 and its height from the axis are always made ~b/ - 15 -:
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constant. In order to facilitate the operation of hanging a ring element 5 havin~ a lar~e distortion on the supporting member 10, the supporting member should be molded to have an outer diameter smaller than a ring diameter narrowed by this distortion (defined by processincJ means for preparing a ring element from a material).
Accordingly, the quantity of correction of the ring element 5 in the radial direction by t~e annular mem~er 11 can be increased and therefore, the length of the top taper 26 of the pick up small diameter portion 17 is increased in proportion to the correction quantity. When the ring element 5 is pressed in the axial direc-tion by the pressing peripheral wall 28 of the annular member 11, the taper 26, the length of which is increased, should be removed outwardly of the inner peripheral face of the ring element 5. On the blockade 9, there is formed an annular recess 35 for locating the lengthened taper 26 when the blockade 9 is maximally expandedO
By this arrangement, when the ring element 5 is pressed in the axial direction, the cylindrical face 18 of the small diameter portion 17 should inevitably confront the inner peripheral face of the ring element 5, whereby the height and position of the ring element 5 can be maintained correctly. When tne ring element is combined with a deeper groove of the tu~ular wall, the ring element is projected outwardly from the blockade 9, the ~iameter of which is maximally expanded. An annular guide 30 having an outward taper is mounted on the blockade 9 to cause the softened zone of the pipe to go beyond the ring element 5 from the outer peripheral face of the blockade 9. This modification ls especially effective when a larger quantity of correction is made on ring elements, it is desired to maintain the height of rings ver~ precisely ox when 29 ring elements are combined with deeper grooves of t~lbular ends.
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In the modification, a top taper 26' for picking-up a ring element, a small diameter portion (7) for correcting the circularity of a ring element 5 and also a radial wall 28' for compressing a ring element to firm:Ly hold and correct the plane-ness of a ring element are formed on the split blockade 9 at the radial side facing the supporting member 10.
The annular member 11 is then provided a radial face 11' on the top end, thereby to compress the ring element 5 between the radial face ll' and the radial wall 28'. The correcting means provided on the split blockade 9 is arranged in a complete annular state when the split blockade g is expanded, and movable pieces 9a may be contracted having respectively a corresponding part of the correcting means those of which are repeatedly formin~ the complete annular shape in expanded state.
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Claims (10)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method for planting a ring element on the inner wall of a pipe of a thermoplastic material along a prescribed length thereof, which comprises the steps of:
assembling, on a common axis side by side, a support-ing member for hanging a ring element thereon and a split blockade which can be deformed to expand or contract the outer diameter thereof, hanging a ring element having an outer diameter larger than the inner diameter of a pipe on said supporting member, expanding said split blockade to block said ring element at the back, mounting a sliding annular member on said supporting member on the side opposite to said split blockade and moving the supporting member in the axial direction to press the ring element to the blockade, locally heating the pipe to soften a zone of the pipe extending from the end to a ring element planting position, inserting said assembly into said softened zone of the pipe, whereby the softened zone is expanded to cause the ring element mounted on said assembly to pass through the softened zone up to the planting position, disposing around the softened zone of the pipe an outer molding member having an inner cavity providing desired appearance and shape on completion of planting of the ring element, pressing said outer molding member to said softened and expanded zone of the pipe to allow the ring element to intrude in the inner wall of the pipe, cooling the pipe to fix said ring element in the pipe in said state, and contracting said split blockade to pass it through said ring element and separating said assembly and outer molding member from the pipe.
assembling, on a common axis side by side, a support-ing member for hanging a ring element thereon and a split blockade which can be deformed to expand or contract the outer diameter thereof, hanging a ring element having an outer diameter larger than the inner diameter of a pipe on said supporting member, expanding said split blockade to block said ring element at the back, mounting a sliding annular member on said supporting member on the side opposite to said split blockade and moving the supporting member in the axial direction to press the ring element to the blockade, locally heating the pipe to soften a zone of the pipe extending from the end to a ring element planting position, inserting said assembly into said softened zone of the pipe, whereby the softened zone is expanded to cause the ring element mounted on said assembly to pass through the softened zone up to the planting position, disposing around the softened zone of the pipe an outer molding member having an inner cavity providing desired appearance and shape on completion of planting of the ring element, pressing said outer molding member to said softened and expanded zone of the pipe to allow the ring element to intrude in the inner wall of the pipe, cooling the pipe to fix said ring element in the pipe in said state, and contracting said split blockade to pass it through said ring element and separating said assembly and outer molding member from the pipe.
2. A method according to claim 1 wherein said outer molding member has an inner annular groove molding cavity and the softened zone of the pipe surrounding the ring element is bent along the ring element in conformity with said groove molding cavity, whereby the ring element is combined with the pipe wall molded to have a groove shape.
3. A method according to claim 1 wherein said sliding annular member and said split blockade to be assembled with each other have an outer peripheral mold having the same shape as that of a desired annular space for containing therein a packing ring, and said annular space is formed simultaneously with the process of planting the ring element in the inner wall of the pipe.
4. A method according to claim 3 wherein a mold, having a peripheral face shaped to provide an enlarged diameter portion in said pipe for receiving therein an end of an inserted pipe, is assembled adjacent said blockade, said pipe is further heated in a zone extending from the ring element planting position to the pipe end inserting position, and the assembly is inserted in the softened zone of the pipe in succession from said mold to said sliding annular member.
5. A method according to claim 1 wherein said sliding annular member has a molding peripheral wall formed to define a small diameter portion extending frontwardly, a tapered portion inclined toward the axis is formed on the top end of said small diameter portion, the inner peripheral face of the ring element hung on said supporting member is picked up and expanded by said tapered portion, and said blockade and said peripheral wall are brought close to each other to press tightly the ring element therebetween and correct the circular configuration by the peripheral face of the small diameter portion to increase the circularity thereof.
6. Apparatus for positioning a ring element on the inner wall of a pipe of thermoplastic material at a predeter-mined distance from one end, comprising:
a cylindrical supporting member for receiving the ring element thereon;
cylindrical mold means coaxially connected to said supporting member;
blockade means concentrically mounted on said supporting member and radially expandable between diameters less than and greater than the diameter of said mold means, said blockade means having an annular face portion engageable with said ring element;
expansion means for radially expanding and contracting said blockade means;
an annular member axially slidable on said supporting member and having a forward face portion engageable with said ring element such that said ring element may be clamped between said annular member and said blockade means; and means for radially expanding said ring element to bring it into contact with the inner wall of the pipe.
a cylindrical supporting member for receiving the ring element thereon;
cylindrical mold means coaxially connected to said supporting member;
blockade means concentrically mounted on said supporting member and radially expandable between diameters less than and greater than the diameter of said mold means, said blockade means having an annular face portion engageable with said ring element;
expansion means for radially expanding and contracting said blockade means;
an annular member axially slidable on said supporting member and having a forward face portion engageable with said ring element such that said ring element may be clamped between said annular member and said blockade means; and means for radially expanding said ring element to bring it into contact with the inner wall of the pipe.
7. Apparatus according to claim 6 wherein said means for radially expanding said ring element includes a bevelled portion of the forward face portion of said annular member engageable with an inner edge of said ring element and a cylindrical recess in said forward face portion of the desired diameter, sliding movement of said annular member forcing said ring element into abutting contact with said blockade means and providing radial expansion of said ring element to a limit defined by said cylindrical recess.
8. Apparatus according to claim 7 wherein said blockade means includes recess means in the face portion thereof to receive the forward edge of said bevelled portion; said expansion means comprises a thrust taper ring having a forward cylindrical step portion of a first diameter and a sloping portion leading from the step portion to an outer portion of a second diameter greater than said first diameter; and said blockade means includes a bevelled edge engageable with said sloping portion so that sliding movement of said taper ring will expand said blockade means from its contracted position, determined by said first diameter, to its expanded position determined by said second diameter.
9. Apparatus according to claim 6 wherein the outer edge of the face portion of said blockade means has a cylindrical recess therein and a bevelled portion leading to said recess so that as said expansion means expands said blockade means and as said annular means slidably engages said ring element to move the ring element towards said blockade means, the ring element will engage said bevelled portion and will be expanded to rest on said cylindrical recess, the final diameter of the ring element being determined by the final expanded position of said blockade means.
10. Apparatus according to claim 6 or claim 9 wherein said expansion means comprises a thrust taper ring having an annular sloping forward surface engageable with a corresponding inner sloping surface on said blockade means whereby sliding movement of said taper ring relative to said blockade means will radially displace said blockade means.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP49140811A JPS5167516A (en) | 1974-12-07 | 1974-12-07 | Kantsugiteno seiho |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1043992A true CA1043992A (en) | 1978-12-12 |
Family
ID=15277279
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA241,013A Expired CA1043992A (en) | 1974-12-07 | 1975-12-04 | Method of planting ring elements on inner walls of pipes or pipe joints |
Country Status (10)
| Country | Link |
|---|---|
| JP (1) | JPS5167516A (en) |
| AT (1) | AT347190B (en) |
| BR (1) | BR7508085A (en) |
| CA (1) | CA1043992A (en) |
| CH (1) | CH603334A5 (en) |
| DK (1) | DK553575A (en) |
| ES (1) | ES443295A1 (en) |
| IT (1) | IT1052535B (en) |
| NO (1) | NO144102C (en) |
| SE (1) | SE418941B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT1133374B (en) * | 1980-11-14 | 1986-07-09 | Sica Spa | MECHANICAL EXPANSION BUFFER FOR THE INTERNAL CALIBRATION OF PLASTIC TUBES IN GENERAL, IN PARTICULAR FOR THE REALIZATION OF SEATS FOR GASKETS |
-
1974
- 1974-12-07 JP JP49140811A patent/JPS5167516A/en active Granted
-
1975
- 1975-12-04 NO NO754102A patent/NO144102C/en unknown
- 1975-12-04 CA CA241,013A patent/CA1043992A/en not_active Expired
- 1975-12-05 CH CH1595375A patent/CH603334A5/en not_active IP Right Cessation
- 1975-12-05 SE SE7513730A patent/SE418941B/en not_active IP Right Cessation
- 1975-12-05 ES ES443295A patent/ES443295A1/en not_active Expired
- 1975-12-05 IT IT52572/75A patent/IT1052535B/en active
- 1975-12-05 BR BR7508085*A patent/BR7508085A/en unknown
- 1975-12-08 DK DK553575A patent/DK553575A/en not_active Application Discontinuation
- 1975-12-09 AT AT935475A patent/AT347190B/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| AT347190B (en) | 1978-12-11 |
| SE418941B (en) | 1981-07-06 |
| DK553575A (en) | 1976-06-08 |
| NO144102C (en) | 1981-06-24 |
| CH603334A5 (en) | 1978-08-15 |
| SE7513730L (en) | 1976-06-08 |
| NO754102L (en) | 1976-06-09 |
| ES443295A1 (en) | 1977-08-16 |
| JPS5167516A (en) | 1976-06-11 |
| JPS5425554B2 (en) | 1979-08-29 |
| IT1052535B (en) | 1981-07-20 |
| ATA935475A (en) | 1978-04-15 |
| BR7508085A (en) | 1976-08-24 |
| NO144102B (en) | 1981-03-16 |
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