CN1156229A

CN1156229A - Separable pushing up pipe joint

Info

Publication number: CN1156229A
Application number: CN 96119242
Authority: CN
Inventors: W·S·迪森
Original assignee: IMI Norgren Ltd
Current assignee: Norgren Ltd
Priority date: 1995-10-11
Filing date: 1996-10-10
Publication date: 1997-08-06

Abstract

A method of making a one-piece, rigid thermoplastics body for a discrete, releasable push-in tube coupling device of the collet type comprises initially injection moulding the body about one or more rigid cores. Each rigid core is then withdrawn axially while the moulding is still in a plastic state whereby the outer, narrower bore portions of the body expand radially. The expanded portions are then radially contracted back to their as-moulded configuration using a jaw-like tool and finally the body is allowed to cool.

Description

Releasable push-in type pipe joint

The present invention relates to a kind of releasable push-in type pipe joint, a kind of like this joint of more specifically saying so, it has a pipe box, in no pipe situation, by insert the joint of can simply pipe box easily being packed into from the outside.Preferably, but not necessarily, under no pipe situation, pipe box easily can be removed again, for example the pipe box of a damage or resemble O shape and encircle the sealing of this class and also formed the joint component that to replace easily by drawing it.Below, this joint is known as " joint of described type ".

The joint of described type is well-known and at first is described in the british patent specification 1520742.A fundamental characteristics of the body of this joint is a pipe receiving bore that comprises a wedge-like portion, its pipe towards body hold end reduce diameter and and the acting in conjunction of sleeve arm make and under the situation that the unexpected pulling of pipe or its fluid pressure increase, more firmly clamp pipe.Therefore pipe is extracted out or is disputed out from the accident of joint and is prevented from.Yet, if desired, be pulled outwardly pipe and it unclamped from joint by inside pushing sleeve pipe.

At first, the body of described type fittings extremely expediently by metal for example to manufacture monomer spare through the brass stamping part of machining, the brass rod of machining or the form of mold.Yet, for many years, the plastics pipe joint is produced wilderness demand, and as passing through facts have proved of numerous manufacturers, although very need, but traditional technology is impossible use the single-piece integral joint of the described type of thermoplastic plastics shaping, this is because of the tower crane in-profile and therefore needs to use instrument costliness, complicated of dismountable core, this core can pass after forming step than the end in the hole of minor diameter and freely extract out, under any circumstance, in fact can not use this instrument to remove the body of the little external diameter pipe joint of this described type.

Therefore, in practice, when the joint of the thermoplastic body of making described type, relative nose end part than minor diameter is provided, it comprises a wedge-like portion, and it is a separating component, is that the subject type spare of cylindricality makes up and together therefore easily with the moulding of single-piece form with inside then.In other words, body has the multi-part formation.For example, B. P. 2120339 has been described a kind of like this formation, and the part that wherein separates moulding can use simple tool with the plastic material moulding, then with being ultrasonically bonded on the subject type spare.Conversion ground, the endless metal inserting member that for example as everyone knows uses the separation that comprises a wedge-like portion to form, itself and subject type spare are combined.Much less, those suggestions have shortcoming, with respect to the single piece of metal body, have comprised the several body parts, so assembly expenses increases.

Because view to above-mentioned shortcoming, International Patent Application WO 94/21953 proposes to change the design of described type fittings body, the wedge-like portion of its mesopore is left out, by substituting with the coefficient sleeved arms of radial groove that is formed on interior cylindrical thermoplastic body, and therefore can be easily with the single piece body moulding.Yet, need to use the sleeve pipe that changes, mean that more be actually necessary, indication goes to cover the outer end of groove with for example plastic sheath really.This needs to produce additional body component and additional combined operation again.

A kind of suggestion with the described type fittings integral body of monomer moulding is disclosed in european patent application 0518679.This propose to use conventional tool comprise rigid core instrument particularly from the material of synthetic rubber or other rubber like with the single-piece formed body.Extract the core instrument like this after synthetic rubber solidifies out, the part of the relative minor diameter of body can expand and automatically return to its shaping position rapidly.Body component is not required in addition, but because their dimensional instability itself is not suitable for using the synthetic rubber body in high-voltage applications, as described in the widely used pneumatic control of type fittings use in neither one additional, the body component of reinforcement is not all right.

At last, nearest disclosed UK Patent Application 2292780 has proposed to be used for the thermoplastic body of the moulding of pipe joint, it is similar to the joint of described type substantially, this application understands especially certainly so far needs to use dismountable core instrument for body formed with the single-piece rigidity plastics, and be used for described type fittings, and the type spare that proposes preformed body is an interior cylindrical, and therefore can use simple rigid core instrument to be shaped with single-piece.Preformed seat end has the formation of some cannelures ground so that they can be continuously radially remove to provide desired last interior wedge profile and they are maintained at this profile by outer metallic sheath to internal strain.Therefore, Fu Jia body component be required and required shaping jig because need to form groove must be more complicated.

Although be a long-standing problem, this problem is discussed by the people that those are familiar with this technology continuously, by the top knowledge of be sure oing so far us rigidity that a suggestion do not use complicated, expensive dismountable core instrument to produce to be used for described type fittings is not proposed also, complete body single-piece, the thermoplastic global formation (promptly this body be similar to original, the extensively available and single piece of metal body that is used).

The present invention propose one to the solution of this problem exquisiteness it utilizes one or more (when being fit to) rigid core instrument with simple aftershaping spare deforming step in conjunction with traditional moulding process.

According to an aspect of the present invention, a moulding monomer that is used for described type pipe joint is provided, the method of rigid thermoplastic's body, this method is used and is comprised that at least one limits the rigid core of bore area, this method comprises, after forming step, extract the body portion that described core passes the relatively little diameter outer end of limiting hole out at axial direction, this body portion comprises wedge-like portion, when body or described at least part during still in plastic state, described part radial expansion, subsequent radially thermoforming dilation is when in plastic state, substantially get back to completed state, and make or the cooling of permission type spare.

The present invention also provides an individuality, by the preceding method manufacturing, is used for the joint of described type, and this joint comprises such body that has two or more elastic packings and the tight sleeve pipe of one or more pipe clamps.

In addition, the invention provides the injection moulding instrument is suitable for using in method of the present invention.

The dilation of fittings body is thermoformed and gets back to (promptly shrinking) in plastic state desired by completed state, and this is to obtain by the device that uses cylindricality mould for example or similar pawl.When body (or described at least dilation) because the result of forming operation preferably follows core during still in plastic state extracts step out and implement collapse step immediately.It can be implemented after reheating operation after a while.

Much less, when employed plastic material during in a kind of like this elevated temperature and so enough plasticity, core is extracted out and collapse step is implemented, and necessary expansion is implemented at the same time there not being other that type spare is out of shape under (for example significant axial deformation) situation.Naturally, the optimum temperature of enforcement extraction and collapse step or temperature range depend on employed concrete plastic material and can be determined rapidly by simple test respectively.At this, as preferable, collapse step is followed core extraction step and is implemented immediately, and the former is producing under the low temperature slightly than the latter, goes to cool off because type spare has many slightly time certainly.

In principle, any thermoplastic plastics shaping material can be used, but crystalline solid preferably, we only mention acetal, polyamide, polypropylene, polyethylene, the poly-rare terephthalate of fourth by example.

The present invention will be described in more detail with reference to the accompanying drawings by example now, wherein:

Fig. 1 is the cross-section side view that the typical straight pipe type joint of a body is arranged;

Fig. 2 a, 2b, the pure step that relates to preferred approach of the present invention that schematically shown of 2c;

The pure method of implementing the collapse step conversion that schematically shows of Fig. 3; With

Fig. 4 is the floor map that is used for the instrument of the method according to this invention combination straight connector body.

Referring to Fig. 1,1 and 2 typical " directly " pipe joints that link together have been represented to manage.Pipe 1 and 2 can be a rigidity or semirigid, but employed joint is used to connect flexible pipe together substantially, for example, and the plastic tube in pneumatic plant particularly.

Joint comprises a monomer column body 3, and it has relative pipe receiving bore to be used to keep separately sleeve 4,5 and O V-shaped ring 6,7.More specifically (referring to the right hand portion of containing pipe 2, left-hand part is same), the hole comprises innermost cylindrical section 8, and it is suitable for the inner of containing pipe 2, and 9 one frustoconical parts 10 of a major diameter cylindrical section axially are being wedged into a minor diameter and outermost cylindrical section 11.Innermost cylindrical section 8 ends at annular shoulder 12 places with its inner, and this shoulder is used for the pipe end braking part of the insertion end of limiter tube 2, and cylindrical section 9 ends at annular shoulder 13 places with its inner, settles O seal ring 7 at this place.O seal ring 7 forms fluid-tight together with pipe 2 and is connected.

The sleeve pipe 5 that is kept by the hole comprises has an all-in-one-piece radially along flange of stretching 15 and inner axially along some (as four to eight) all-in-one-piece of stretching, arm 16 spaced apart from each other etc. from it by the cylindrical section 14 of cylindrical section 11 sliding supports in the hole of body 3 and in its outer end.Each arm that can radially bend 16 has the inner of expansion, and it has tight projection of sharp-pointed pipe clamp or " tooth " 17.Sleeve pipe 5 was by inserting most external 11 when no pipe (certainly) body 3 of packing into simply, in case radially curve inwardly by the gap between them and sleeve pipe has been inserted into the normal position that turns back to them at this process arm 16.Typically sleeve pipe 4 and 5 is made by a brass, they each also can replace by for example shaped plastics spare.

It is connected simply up to its close shoulder 12 with O shape ring 7 by pipe box 5 by ejector sleeve 2.Tooth 17 is caught pipe 2 slightly in normal circumstances.Yet when pipe 2 is spurred or within it fluid pressure when increasing by accidental, pipe box 5 slightly outwards moves axially, so the bellend acting in conjunction of the truncated cone part 10 in hole and pipe box wall 16 forces arm 16 radially inside; Having increased their clamping and prevention pipes 2 on pipe 2 unexpectedly extracts out or ejection from connect.Yet pipe 2 can be by inside pressure pipe cover 5 and trombone slide 2 and extraction from connect simultaneously.Pipe 2 can reconnect with the above-mentioned mode that relates to.

When not having pipe, pipe box 5 can be extracted out simply by being pulled outwardly it, is enough to make them to pass through the narrow path portion 11 in hole so wall 16 at interval radially bends.Therefore, replace easily an impaired sleeve pipe 5 or, in case sleeve pipe is removed, replace the O V-shaped ring 7 of a damage.

Flange 15 on the sleeve pipe is chosen wantonly, but it makes and assembles together with body 3 or unload from body 3 that manual gland pipe is easy as throwing off pipe when expectation from is connected.

As above-mentioned example shown as described in the pipe of type connect, in the present technique field, be known, even for example can be with these cylindrical hole part 11 deletions, just then this frustoconical part 10 is had a basic demand.Those are by the metal manufacturing with a body made in one piece always so far, and as noticing, those have rigid thermoplastic's body then all to have the multi-part body to constitute all the time.

Fig. 2 a to 2c has represented method of the present invention, at this, whole body 3 can by rigidity, thermoplastic is with the moulding of single type ground.

At first referring to Fig. 2 a, show after the injection molding technology moulding of part with routine of connecting body of described type, but before the rigid column core instrument that the internal surface of formed body 3 parts is required 18 is extracted out.More specifically, will see described part identical with the right hand portion of single piece body 3 shown in Figure 1 more or less and really Fig. 2 a to 2c provided each same reference number.

When build spare 3 (or to small part 10 and 11) along with forming operation still is a plasticity, core instrument 18, after the external tools (not shown) that is used to form build spare 3 is separated, with axially pulling out fully of arrow A, in cylindricality step 19 (being its maximum diameter part) the described part 10 of radial expansion (frustoconical part) and the part 11 (outermost cylindrical section) of this process core instrument 18.In this process, type spare is tied by abutting against moving axially of shaping jig spare.Last type spare is illustrated among Fig. 2 b, although in the character that to a certain degree depends on employed plastics, the radial expansion part can be lax slightly towards its original shaped form.Type spare shown in Fig. 2 b can be cooled with reheat the back be thermoformed to provide the type spare shown in Fig. 2 c at different stations.Yet ideally, the thermoforming step has been extracted out fully and has been carried out immediately when type spare also is in enough plastic statees owing to shaping operation at the core instrument.

Under any circumstance, thermoforming step comprise dilation basically radial contraction get back to its forming shape shown in Fig. 2 a and the 2c.This can use semi-cylinder pawl 20,20 ' for example a pair of as that radially be shown in Fig. 2 b and 2c to realize offside, this pawl closure radially on the direction of arrow B (part Fig. 2 b).This pawl 20,20 ' can be combined in the chamber of the separation in this main body forming blocks.Yet,, also can adopt such as the additive method that uses a kind of cylindricality former as schematically being shown among Fig. 3.

Shown in Fig. 2 b, Fig. 3 illustrates the type spare after the extraction tool core 18.The radial contraction of this dilation is to be at it to move axially a former 21 on arrow C direction of plastic state lower edge realize on dilation.As can be seen, die nozzle 22 is wedge shape, so that make former 21 acceptant dilations.

Type spare is cooled to provide last body after collapse step.

Notice that as top any thermoplastic material can be used basically, though for example a kind of acetals of our preferred crystalline solid " engineering " plastics (is HOSTAFORM as trade mark) or a kind of polyamide (as nylon 6).For this special material, collapse step is normally carried out under about 150 ℃ temperature, and the core that carried out before being right after collapse step is extracted step out and then carried out under high slightly promptly about 155-165 ℃ temperature.

Turn back to Fig. 2 a, can see, the body that internal surface has two or more pipes to hold end is formed by corresponding core 18.Like this, need use two cores, and normally when type spare also has enough plasticity, on opposite axial direction, they be extracted out simultaneously with the straight connector of type shown in Figure 1.

The pure example that schematically shows an instrument of Fig. 4.This instrument is used for according to method moulding of the present invention union body always.Instrument comprises two and

half parts

23 and 24, and one of them half part 23 is fixed, and another half-open 24 can be in direction lateral movement shown in the double-head arrow D, and carries two

core instruments

18 and 18 '.Fig. 4 be illustrated in formed body 3 and separates the back with 24 by 24 lateral movements of half part and with two and half parts 23 but at the instrument before the core instrument extracted out when this instrument half part 24 during with main forming process lateral movement, formed body 3 by support and driving core instrument 18 and 18 ' lever system 25 and 26 shifted out the interior die cavity of half part 24 of instrument by side direction.

As can be seen, body 3 has central authorities, outer ring groove 27.And during the die cavity in formed body shifts out half part 24 of instrument as previously mentioned, little spring brake 28 is driven into groove 27 on half part 24 that is installed in instrument.Break 28 is used for when making body also in the temperature of a rising and therefore also in plastic state because of forming operation, when core instrument 18 and 18 ' obligatory point 3 and opposing moves axially when axially being extracted out continuously by lever system 25 and 26.

Body 3 is sent to another station (not shown) with its expansion end at once after core instrument 18 and 18 ' is extracted out, and at this, when also in plastic state, their profile is got back in the dilation contraction.As noticing previously, be used to realize that the instrument that shrinks can be combined in

instrument half part

23 and 24, and like this, can be in the closed again collapse step that occurs when preparing another body 3 of moulding of this

half part

23 and 24 subsequently, or the like.

Certainly, this method monomer joint that can be used for described type any desired contour of moulding or size includes but not limited to straight type, T type and elbow joints and is used to be incorporated into pneumatic valve for example or the chuck type joint of cylindrical body.To show that also this method is suitable for full automation well.

Claims

1. the one-tenth method of rigid thermoplastic's body of a monomer that is used for a kind of pipe joint, this joint has a pipe receiving bore, described hole comprises that one is held the wedge-like portion that end reduces towards the pipe of body on diameter, and through described pipe end and the tight sleeve pipe acting in conjunction of pipe clamp that can insert described body, under no pipe situation, comprise that by use the instrument of at least one rigid core limits the bore area of described body, it is characterized in that the step of described method also comprises; After forming step, when described body or at least its described part also under plastic state, pass the outer end portion of the less body of the diameter in the described hole of described qualification in the axial direction and comprise that passing its wedge-like portion extracts described core out, thereby described part is radially expanded, when still under plastic state, the described dilation of thermoforming is subsequently got back to its completed state basically, and makes described profiled member cooling.

2. the method for claim 1 is characterized in that the dilation of described body centers on a plurality of pawls thermoforming radially of described part by closure.

3. the method for claim 1 is characterized in that the dilation of described body passes through the thermoforming radially of cylindricality former.

4. as any described method in the claim 1 to 3, it is characterized in that since the result of described body formed operation and described body still under plastic state, and then the extraction step of described core is carried out the thermoforming step at once.

As any described method in the claim 1 to 4 make pipe joint, it is characterized in that described pipe joint comprises the body that the rigid thermoplastic of a single-piece makes.

6. pipe joint as claimed in claim 5 is characterized in that described pipe joint comprises a seal arrangement and the tight sleeve pipe of at least one pipe clamp.

7. the employed injection moulding instrument of the method for claim 1 is characterized in that described instrument comprises:

A) first and second mutual separable instrument half parts, described instrument half part is in wherein limiting corresponding die cavity, and described die cavity is combined into the outer surface that together limits described pipe joint;

B) at least one is used to limit the rigid core instrument of the internal surface of described pipe joint;

C) be used for separating the device of described instrument half part according to the moulding of described body;

D) after separating described instrument half part, be used for device, the body of the described moulding between the described mold half outside the above device of described position is supported on described die cavity at a described rigid core instrument of position upper support;

E) be used for radially extracting the device of described rigid core instrument out from the body of described moulding during in described position when described formed body, thus the less bore portion of described diameter of the described body that radially expands;

F) be used for stoping the axially movable device of described body in the process of extracting the rigid core instrument out.

8. instrument as claimed in claim 7, it is characterized in that described being used for stops the axially movable device of described body to comprise the braking device that is carried by one of described two instrument half parts in the process of extracting the rigid core instrument out, and when the position of described body in the described die cavity outside, described braking device engages the outer groove in the described formed body.

9. as claim 7 or 8 described instruments, it is characterized in that described instrument half part comprises that also texturing device is suitable for after the closure dilation of described body being shunk so that get back to its original completed state again at it.

10. instrument as claimed in claim 9 is characterized in that described warp tool comprises a pair of semi-cylinder pawl, and described semi-cylinder pawl is suitable for around the dilation of described body closed so that described dilation is shunk.