CA1309119C - Adapter for plastic pipe - Google Patents
Adapter for plastic pipeInfo
- Publication number
- CA1309119C CA1309119C CA000565231A CA565231A CA1309119C CA 1309119 C CA1309119 C CA 1309119C CA 000565231 A CA000565231 A CA 000565231A CA 565231 A CA565231 A CA 565231A CA 1309119 C CA1309119 C CA 1309119C
- Authority
- CA
- Canada
- Prior art keywords
- passageway
- adapter
- bore
- shoulder
- insert
- 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 - Lifetime
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- Branch Pipes, Bends, And The Like (AREA)
Abstract
ADAPTER FOR PLASTIC PIPE
ABSTRACT OF THE DISCLOSURE
This invention relates to an adapter for connecting a non-metallic pipe to a threaded metallic element, such as a sprinkler head, in leak-tight fluid communication. The adapter comprises a plastic coupling unit which is adhesively secured at one end to plastic pipe and adapted at the other end thereof to receive a threaded metal insert which may be threadably connected to a metal element, such as a sprinkler head, The adapter of the invention is particularly suitable for use in high pressure fire extinguishing systems.
ABSTRACT OF THE DISCLOSURE
This invention relates to an adapter for connecting a non-metallic pipe to a threaded metallic element, such as a sprinkler head, in leak-tight fluid communication. The adapter comprises a plastic coupling unit which is adhesively secured at one end to plastic pipe and adapted at the other end thereof to receive a threaded metal insert which may be threadably connected to a metal element, such as a sprinkler head, The adapter of the invention is particularly suitable for use in high pressure fire extinguishing systems.
Description
130~1 19 ADAPTER FOR PLASTIC PIPE
BACKGROUND OF THE INVENTION
This invention relates to an adapter ~or connecting a threaded metal element to a plastic pipe in high pressure system~ and particularly to an adapter for connecting a matal sprinkler head to pla tic pipe in fire extinguishing sprinklar systems.
Conventional fire extinguishing systems generally comprise a network of piping for delivery of a fire extinguishant such as water to variou~ locations throughout a building through sprinkler heads provided at the end of each plpe segment. The sprinkler heads are activated whan the surrounding temperatures exc2ed an upper limit which causes a low melting point alloy in the sprinkler head~ to melt.
Fire extinguishing systems ,utilizing plastic pipe aro usually wet sy3tems because water under high pre~sure (e.g., 200 p~i or mora) i~ maintained in the pipe to prevent heat damage thereto. However, prior pipe 3yst~ms wer~ ~raquently sub~eat to ~ailure at the threaded connection between a plastic adapter which is adhQ~ively ~ecure~ at one end thereo~ to the plastic pip~ and threadably connected to the metal sprinkler head at the other end. The pla~tic threads of the adapter were found to be 3ubject to attack by the ~olv~nt adhesive used to secure the adapter to the end of the plastic pipe. Moreover, srack~ in the plastic coupling were frequen~ly encountered due to overtightening of ~he metal sprinkler head.
Cro~ threading wa~ al~o a problem when installing the sprinkler head to the pla~t$c adapter.
To a~oid ~ome o~ the~e problems, brass inserts wlth thread~ have been incorporated into the end of pl~tic adapter~ during the for~ation thereof.
Additionally, metal collars have been mounted around th~ exterior o~ the plastic adaptar in order to prov de ~ .
- ~:
130~1 19 support and to minimize the cracking th~:reo~ when mounting the sprinkler headO While these modifications reduced somewhat the frequency of failures, they~ were very expensive and very inconvenient to employ in the manufacturing procedures, particularly with conventional injection molding procedures utilized to manufacture the plastic adapter~.
What ha~ been needed and heretofore unavailable is a simple, inexpensive adaptsr to connect plastic pipe to a threaded metal element, such as a sprinkler head, which maintain~ a sound, leak-proof connection under high pressure systems. The present invention satisfies that need.
S~MMARY OF ~HE INVENTION
~ he pre~ent invention is directed to an improva~ adapter for connecting a threaded metal elemQnt, 0uch a~ a sprinkler nozzle, ~o a plastic pipe which i3 particularly ~uitable for uqe in hlgh pressure ! syst~m~, guch ~g ln ~ire ~xtinguishing systems.
The adaptar in accordance with the present invQntion comprisQs an open~ended tubulax plastic coupling unit having a bor~ or interior ~assageway interaonnecting the two end~ thereof with an annular pro~sction or bu~hing and a threaded metal insert at least partially disposed. within the plastic coupling unit. The internal bu~hing within the internal pa~ageway of the coupling guides and positions the male end o~ the metal insert within the coupling unit.
The male end of the metal inser~ disposed within the coupling unit i3 ~nlarged to a diameter greater than 3Q the inn~r diameter of the annular projec~ion or bushing wi~hin the passagaway of the coupling uni~ to prevent the removal of the mel:al incert from the female end of the coupling uni:t.
In a preferred embodiment, th~ inner surface :
130ql 19 of the bushing is provided Wit.l a plurality of elongated teeth or ~errations which are adaptsd to engage the elongated teeth or serrations providèd on ~he exterior surface of the male end of the insert in order to prevent the relative axial rotation of the metal insert within the coupling unit when a metal sprinkler head or other metal element is threadably mounted to the adapter.
The open-ended, tubular plastic coupling unit is provided with a first free end which is adapted to be coupled in fluid communication with the end of a plastic pipe, such as by a sui~able solvent adhesive, and a s~cond female end adapted to receive the threaded metal insert. The male end of ths threaded metal insert, which is inserted into the plastic coupling unlt, is pra~erably cylindrically shaped and, after the insert is position~d within the passageway of the aoupling unit, is ~lared outwardly, such as by roll forming, to thereby lock thQ metal insert within the plaskic coupling unit to prevent axial movement of the insart koward th~ female end o~ the coupling unit. The ~emale end o~ the coupling unit i3 provided with a stepp~d inner sur~ace which interfits wlth the stepped interior sur~ac~ o~ the male end of the insert to en~ure that th~ insert is properly positioned wi~hin tho coupling un.lt. The free end o~ the metal insert is provided with threads which allow connection to a thread~d metal element, such as a prinkler head. The threads may b~ interior or exterior depending upon ~he nature of the attached threaded element.
An elastomeric or rubber O-ring is disposed within a circum~erential groove dePined between the exterior surface o~ the metal insert and the interior surface of the plastic coupling unit to prevent fluid leakage therebetween.
To ~ssemble the adapter, the metal insert is positioned wi~hin th~ bore of the coupling unit with .. .
1 30q 1 1 9 the teeth or serrations pro~erly aligned, the insert is pressed into the coupling body to intermesh the teeth or serrations, and then the inserted male end o~ the insert is roll formed so a~ to ~lare outwardly against the edge of the bushing axially distant ~rom the female ~nd o~ the coupling unit to lock the metal insert within the passageway of the coupling unit. A
sprinkler head or other threaded element may then be threadably connected to the metallic threads of the insert. The threaded connection is metal-to-metal so there is little likelihood o~ cracking or other damage to the threads. Moreover, the solvent adhesive used to connect the adapter to the end of the plastic pipe will not have any significant effect on the metallic threads.
Ths3e and other advantages o~ the present invention will become more apparent from the following detailed description of the invention, when taken in con~unction with the exemplary drawings.
! ~RIEF D~SC~IPTION OF THE DRAWINGS
FIG. 1 i~ a per~pective view, partially in section, of an adapt~r embodying ~eatures o~ the invention which conneats a plastic pipe in fluid commun~cation with a sprinkler head;
FIG. 2 is an exploded view, partially ln seotion, o~ the adapter shown in FIG. l;
FIG. 3 1~ an el~vational cross-sectional view o~ the adapter shown in FIG. l; and : FIG. 4 iB a cros~-sectional view ~aken along ~he line~ 4-4 shown in FIG. 3~
DETAILED DESCRIPTION_OF TH~ INVENTION
Reference ic made to FIG. 1 which illustrates an adapter lO ~mbodying features of the invention for 1 30q~ 1q connecting a threaded metallic element, such as a sprinkler head 11, to a plastic pipe 12 which may be part of a high pressure, water-based fire extinguishing system 5With particular reference to FIGS. 1 through 3, the adapter 10 of tha invention generally comprises a non-metallic coupling unit 13 and a metal insert 14 which is adapted to be inserted into one end of the coupling unit 13. The tubular shaped coupling unit 13 10has a first free end 15 which is adapted to be connected by suitable maans, such as solvent adhesive, to plastic pipe 12 and a second female end 1~ which is adapted to receiv~ the male end 17 of the tubular shaped metal insert 14. The metal insert 14 has a 15threaded free end 18 which is adapted to be threadably connected to a threaded metal element, such as a fire extinguishing sprinkler head 11, shown ln FIG. 1.
A~ shown more clearly in FIGS. 2 and 3, the coupling unit 13 i3 provided with an internal bore or 20pa~sageway 20 having an annular pro~ection or bushing 21 to guide and positlon the male end 17 of the metal insart 14 during th~ insertion thereof. The male end 17 of the metal insert 14 whlch i~ disposed within the coupling unit 13, i~ enlarged after insertion to an 25outer diameter greater than the inner diameter of the interior annular pro~eation or bushing 21 to prevent the withdrawal o~ the me~al in~rt 14 ~rom the female end 16 o~ the coupling unit 13~
The metal insert 14 generally has a stepped 30exterior ~ur~ace which matches and inter~its with the stepped inner sur~ace of the coupling unit 13. A first circumferential shoulder ~2 on the m~al insert 14 acts a a stop ~or the tapered ~emale end 16 of ths coupling unit 13. A ~econd circumferential shoulder 23 of the 35m~tal insert 14 acts as a stop ~or shoulder 35 on the coupling unit 13 and also de~ines in par~, in con~unction with the end 24 of ths annular projection `~'`'`' ' :. - ~ , .
.. -. . . .
, ,' ' ' ' .
130ql 19 or bushin~ ~1 of the coupling unlt 13 nearest the female end 16, a circum~erential groove 25 adapted to receive a suitable rubber or elastomeric 0-ring 26 which pr~vents the pa~age of fluid between the coupling unit 13 and the metal insert 14.
To facilitata lnsextion into the coupling unit 13, the male end 17 of the metal insert 14 is initially cylindrlcal in shape, as shown ln FIG. 2t with an outer diameter 195 than the inner diameter of the inwardly projecting bushing 21 of the coupling unit. once the inse~t 14 i8 properly positioned within the bore 20 of th~ coupling unit 13, the male end 17 thereof is flared outwardly prefera~ly by roll for~ing to lock the insert. A~ shown more clearly in FIG. 3, the outer edg~ 30 of the flared end 17 of the metal insert 14 forms a recess 31 with the distant end 24 of the inwardly projeoting bushing 21 to capture excess solvant adhasive when the free end 15 of the coupling unit 13 i~ adhesively seaured to the end of plastic pipe 12.
Tha sur~ace of the bu~hing 21 and the exterior surface of th~ male end 17 of the metal insert 14 are both provided with inter~ittlng slongated teeth or ~erratione 32 and 33, raspectively, which when engaged prevent rotation between the coupling unit 13 and the metal Ln~ert 14. In this manner, when a threaded metallic element, ~uch as a sprinkler head 11, is threadably coupled to threaded end 18 of the insert 14 and tlghtened, th~ insert 14 will not rotate about its longitudinal axi~. Aa ~hown in FIGS. 2 and 4, there are 36 individual elon~ated teeth or serra~ions around both th~ inner pariphery of the buching 21 and the ex~erior ~urfacs of ~he m~tal insert 14. ~owever, the number of tee~h or ~erration~ can vary dapending upon the diameter. ~he inter~it ef the triangular shaped tee~h 32 and 33 are best shown in FIG. 4. A xidge 34 of the bu~hing 21 provide~ a radius to eliminate , . ' ~, .
. ~ .
13091 ~9 cracking of end 17 when flared ~n the coupling unit.
When assembled, the triangular teeth 33 on metal insert 14 do not contact distant end 24 of bushing 21, leaYing a cmall void 3 6 which acts as a collector ~or any 5 plastic material that is sheared during assembly. This eliminates the need for chip removal.
If de~ired, other types o~ interfitting surface3, such as kalurled or even threaded ~urfaces, may be employed, zllthough in the latter instance, 10 relative rotational moYemerlt would be necessary to tighten the metal insert 14 within the coupling unit 13 .
To as~emble th~ adapter lO of the present invention, an O-ring 2~ i~ po~itioned wi~hLn the a~nular groov~ 25 and then the male end 17 o~ the in~ert 14 is pre~sed into the remals end 1~ of the coupling unit 13 a~ter proper alignment so that the elongated teeth 32 and 33 properly interfit. The in~ert 14 ls pre~sed into the coupling unit 13 untll end 16 o~ thQ coupling unit 13 engag~s the shoulder 22 proYid~d on the ext~rior Or the m~tal insert 14. The cylindrically ~hapHd male ~nd o~ tha metal insert 14 is then ~lared outwardly ~o as to pre~s against the di~tant end 24 og th~ bu~hlng 21 and thereby lock the metal in~ert 14 wi~hin the coupling unit 13.
The coupling unit 13 may be ~ormed in any sui~abîe ~nannor but preferably :i ~ in~ection molded from h~gh impaGt re~i~tant pl~stic ~aterial~, such as chlorinated polyvinyl chlor~de and polybutylene. Other 30 laaterlal~, such a~ ~bergla~, may alE~o b~ used. The Dlatal in~ert i pre~erably machined ~rom bra~3 stock to prov~ d~ th~ lthreads and other dQtailed ~ur~ace conrlgurations. O~h~r m~als such as ~luminu~ ~ay also be used.
q'he adapter or the pressn~ inven~ion provides ~ lsak-t~ght connection b~tween a non-metallic pipe and a threaded m2tal ~ ne~lt at high ~luld pre~sures over . -~ . , ~ , , ' " ,, :.
.
130ql 19 extended periods. There is little or no tendency for the adapter to crack during the mounting of the metal element or during use.
Although the adapter is described herein primarily in conjunction with a high pressure fire extinguishing system, other uses are contemplated. For example, the adapter can be used in high pressure agricultural irrigation systQms. Moreover, various modifications and improvements can be made to the 10 present Lnvention without departing from the scope thereof.
., .
. . . .
BACKGROUND OF THE INVENTION
This invention relates to an adapter ~or connecting a threaded metal element to a plastic pipe in high pressure system~ and particularly to an adapter for connecting a matal sprinkler head to pla tic pipe in fire extinguishing sprinklar systems.
Conventional fire extinguishing systems generally comprise a network of piping for delivery of a fire extinguishant such as water to variou~ locations throughout a building through sprinkler heads provided at the end of each plpe segment. The sprinkler heads are activated whan the surrounding temperatures exc2ed an upper limit which causes a low melting point alloy in the sprinkler head~ to melt.
Fire extinguishing systems ,utilizing plastic pipe aro usually wet sy3tems because water under high pre~sure (e.g., 200 p~i or mora) i~ maintained in the pipe to prevent heat damage thereto. However, prior pipe 3yst~ms wer~ ~raquently sub~eat to ~ailure at the threaded connection between a plastic adapter which is adhQ~ively ~ecure~ at one end thereo~ to the plastic pip~ and threadably connected to the metal sprinkler head at the other end. The pla~tic threads of the adapter were found to be 3ubject to attack by the ~olv~nt adhesive used to secure the adapter to the end of the plastic pipe. Moreover, srack~ in the plastic coupling were frequen~ly encountered due to overtightening of ~he metal sprinkler head.
Cro~ threading wa~ al~o a problem when installing the sprinkler head to the pla~t$c adapter.
To a~oid ~ome o~ the~e problems, brass inserts wlth thread~ have been incorporated into the end of pl~tic adapter~ during the for~ation thereof.
Additionally, metal collars have been mounted around th~ exterior o~ the plastic adaptar in order to prov de ~ .
- ~:
130~1 19 support and to minimize the cracking th~:reo~ when mounting the sprinkler headO While these modifications reduced somewhat the frequency of failures, they~ were very expensive and very inconvenient to employ in the manufacturing procedures, particularly with conventional injection molding procedures utilized to manufacture the plastic adapter~.
What ha~ been needed and heretofore unavailable is a simple, inexpensive adaptsr to connect plastic pipe to a threaded metal element, such as a sprinkler head, which maintain~ a sound, leak-proof connection under high pressure systems. The present invention satisfies that need.
S~MMARY OF ~HE INVENTION
~ he pre~ent invention is directed to an improva~ adapter for connecting a threaded metal elemQnt, 0uch a~ a sprinkler nozzle, ~o a plastic pipe which i3 particularly ~uitable for uqe in hlgh pressure ! syst~m~, guch ~g ln ~ire ~xtinguishing systems.
The adaptar in accordance with the present invQntion comprisQs an open~ended tubulax plastic coupling unit having a bor~ or interior ~assageway interaonnecting the two end~ thereof with an annular pro~sction or bu~hing and a threaded metal insert at least partially disposed. within the plastic coupling unit. The internal bu~hing within the internal pa~ageway of the coupling guides and positions the male end o~ the metal insert within the coupling unit.
The male end of the metal inser~ disposed within the coupling unit i3 ~nlarged to a diameter greater than 3Q the inn~r diameter of the annular projec~ion or bushing wi~hin the passagaway of the coupling uni~ to prevent the removal of the mel:al incert from the female end of the coupling uni:t.
In a preferred embodiment, th~ inner surface :
130ql 19 of the bushing is provided Wit.l a plurality of elongated teeth or ~errations which are adaptsd to engage the elongated teeth or serrations providèd on ~he exterior surface of the male end of the insert in order to prevent the relative axial rotation of the metal insert within the coupling unit when a metal sprinkler head or other metal element is threadably mounted to the adapter.
The open-ended, tubular plastic coupling unit is provided with a first free end which is adapted to be coupled in fluid communication with the end of a plastic pipe, such as by a sui~able solvent adhesive, and a s~cond female end adapted to receive the threaded metal insert. The male end of ths threaded metal insert, which is inserted into the plastic coupling unlt, is pra~erably cylindrically shaped and, after the insert is position~d within the passageway of the aoupling unit, is ~lared outwardly, such as by roll forming, to thereby lock thQ metal insert within the plaskic coupling unit to prevent axial movement of the insart koward th~ female end o~ the coupling unit. The ~emale end o~ the coupling unit i3 provided with a stepp~d inner sur~ace which interfits wlth the stepped interior sur~ac~ o~ the male end of the insert to en~ure that th~ insert is properly positioned wi~hin tho coupling un.lt. The free end o~ the metal insert is provided with threads which allow connection to a thread~d metal element, such as a prinkler head. The threads may b~ interior or exterior depending upon ~he nature of the attached threaded element.
An elastomeric or rubber O-ring is disposed within a circum~erential groove dePined between the exterior surface o~ the metal insert and the interior surface of the plastic coupling unit to prevent fluid leakage therebetween.
To ~ssemble the adapter, the metal insert is positioned wi~hin th~ bore of the coupling unit with .. .
1 30q 1 1 9 the teeth or serrations pro~erly aligned, the insert is pressed into the coupling body to intermesh the teeth or serrations, and then the inserted male end o~ the insert is roll formed so a~ to ~lare outwardly against the edge of the bushing axially distant ~rom the female ~nd o~ the coupling unit to lock the metal insert within the passageway of the coupling unit. A
sprinkler head or other threaded element may then be threadably connected to the metallic threads of the insert. The threaded connection is metal-to-metal so there is little likelihood o~ cracking or other damage to the threads. Moreover, the solvent adhesive used to connect the adapter to the end of the plastic pipe will not have any significant effect on the metallic threads.
Ths3e and other advantages o~ the present invention will become more apparent from the following detailed description of the invention, when taken in con~unction with the exemplary drawings.
! ~RIEF D~SC~IPTION OF THE DRAWINGS
FIG. 1 i~ a per~pective view, partially in section, of an adapt~r embodying ~eatures o~ the invention which conneats a plastic pipe in fluid commun~cation with a sprinkler head;
FIG. 2 is an exploded view, partially ln seotion, o~ the adapter shown in FIG. l;
FIG. 3 1~ an el~vational cross-sectional view o~ the adapter shown in FIG. l; and : FIG. 4 iB a cros~-sectional view ~aken along ~he line~ 4-4 shown in FIG. 3~
DETAILED DESCRIPTION_OF TH~ INVENTION
Reference ic made to FIG. 1 which illustrates an adapter lO ~mbodying features of the invention for 1 30q~ 1q connecting a threaded metallic element, such as a sprinkler head 11, to a plastic pipe 12 which may be part of a high pressure, water-based fire extinguishing system 5With particular reference to FIGS. 1 through 3, the adapter 10 of tha invention generally comprises a non-metallic coupling unit 13 and a metal insert 14 which is adapted to be inserted into one end of the coupling unit 13. The tubular shaped coupling unit 13 10has a first free end 15 which is adapted to be connected by suitable maans, such as solvent adhesive, to plastic pipe 12 and a second female end 1~ which is adapted to receiv~ the male end 17 of the tubular shaped metal insert 14. The metal insert 14 has a 15threaded free end 18 which is adapted to be threadably connected to a threaded metal element, such as a fire extinguishing sprinkler head 11, shown ln FIG. 1.
A~ shown more clearly in FIGS. 2 and 3, the coupling unit 13 i3 provided with an internal bore or 20pa~sageway 20 having an annular pro~ection or bushing 21 to guide and positlon the male end 17 of the metal insart 14 during th~ insertion thereof. The male end 17 of the metal insert 14 whlch i~ disposed within the coupling unit 13, i~ enlarged after insertion to an 25outer diameter greater than the inner diameter of the interior annular pro~eation or bushing 21 to prevent the withdrawal o~ the me~al in~rt 14 ~rom the female end 16 o~ the coupling unit 13~
The metal insert 14 generally has a stepped 30exterior ~ur~ace which matches and inter~its with the stepped inner sur~ace of the coupling unit 13. A first circumferential shoulder ~2 on the m~al insert 14 acts a a stop ~or the tapered ~emale end 16 of ths coupling unit 13. A ~econd circumferential shoulder 23 of the 35m~tal insert 14 acts as a stop ~or shoulder 35 on the coupling unit 13 and also de~ines in par~, in con~unction with the end 24 of ths annular projection `~'`'`' ' :. - ~ , .
.. -. . . .
, ,' ' ' ' .
130ql 19 or bushin~ ~1 of the coupling unlt 13 nearest the female end 16, a circum~erential groove 25 adapted to receive a suitable rubber or elastomeric 0-ring 26 which pr~vents the pa~age of fluid between the coupling unit 13 and the metal insert 14.
To facilitata lnsextion into the coupling unit 13, the male end 17 of the metal insert 14 is initially cylindrlcal in shape, as shown ln FIG. 2t with an outer diameter 195 than the inner diameter of the inwardly projecting bushing 21 of the coupling unit. once the inse~t 14 i8 properly positioned within the bore 20 of th~ coupling unit 13, the male end 17 thereof is flared outwardly prefera~ly by roll for~ing to lock the insert. A~ shown more clearly in FIG. 3, the outer edg~ 30 of the flared end 17 of the metal insert 14 forms a recess 31 with the distant end 24 of the inwardly projeoting bushing 21 to capture excess solvant adhasive when the free end 15 of the coupling unit 13 i~ adhesively seaured to the end of plastic pipe 12.
Tha sur~ace of the bu~hing 21 and the exterior surface of th~ male end 17 of the metal insert 14 are both provided with inter~ittlng slongated teeth or ~erratione 32 and 33, raspectively, which when engaged prevent rotation between the coupling unit 13 and the metal Ln~ert 14. In this manner, when a threaded metallic element, ~uch as a sprinkler head 11, is threadably coupled to threaded end 18 of the insert 14 and tlghtened, th~ insert 14 will not rotate about its longitudinal axi~. Aa ~hown in FIGS. 2 and 4, there are 36 individual elon~ated teeth or serra~ions around both th~ inner pariphery of the buching 21 and the ex~erior ~urfacs of ~he m~tal insert 14. ~owever, the number of tee~h or ~erration~ can vary dapending upon the diameter. ~he inter~it ef the triangular shaped tee~h 32 and 33 are best shown in FIG. 4. A xidge 34 of the bu~hing 21 provide~ a radius to eliminate , . ' ~, .
. ~ .
13091 ~9 cracking of end 17 when flared ~n the coupling unit.
When assembled, the triangular teeth 33 on metal insert 14 do not contact distant end 24 of bushing 21, leaYing a cmall void 3 6 which acts as a collector ~or any 5 plastic material that is sheared during assembly. This eliminates the need for chip removal.
If de~ired, other types o~ interfitting surface3, such as kalurled or even threaded ~urfaces, may be employed, zllthough in the latter instance, 10 relative rotational moYemerlt would be necessary to tighten the metal insert 14 within the coupling unit 13 .
To as~emble th~ adapter lO of the present invention, an O-ring 2~ i~ po~itioned wi~hLn the a~nular groov~ 25 and then the male end 17 o~ the in~ert 14 is pre~sed into the remals end 1~ of the coupling unit 13 a~ter proper alignment so that the elongated teeth 32 and 33 properly interfit. The in~ert 14 ls pre~sed into the coupling unit 13 untll end 16 o~ thQ coupling unit 13 engag~s the shoulder 22 proYid~d on the ext~rior Or the m~tal insert 14. The cylindrically ~hapHd male ~nd o~ tha metal insert 14 is then ~lared outwardly ~o as to pre~s against the di~tant end 24 og th~ bu~hlng 21 and thereby lock the metal in~ert 14 wi~hin the coupling unit 13.
The coupling unit 13 may be ~ormed in any sui~abîe ~nannor but preferably :i ~ in~ection molded from h~gh impaGt re~i~tant pl~stic ~aterial~, such as chlorinated polyvinyl chlor~de and polybutylene. Other 30 laaterlal~, such a~ ~bergla~, may alE~o b~ used. The Dlatal in~ert i pre~erably machined ~rom bra~3 stock to prov~ d~ th~ lthreads and other dQtailed ~ur~ace conrlgurations. O~h~r m~als such as ~luminu~ ~ay also be used.
q'he adapter or the pressn~ inven~ion provides ~ lsak-t~ght connection b~tween a non-metallic pipe and a threaded m2tal ~ ne~lt at high ~luld pre~sures over . -~ . , ~ , , ' " ,, :.
.
130ql 19 extended periods. There is little or no tendency for the adapter to crack during the mounting of the metal element or during use.
Although the adapter is described herein primarily in conjunction with a high pressure fire extinguishing system, other uses are contemplated. For example, the adapter can be used in high pressure agricultural irrigation systQms. Moreover, various modifications and improvements can be made to the 10 present Lnvention without departing from the scope thereof.
., .
. . . .
Claims (10)
1. An adapter for connecting a threaded metal element to a non-metallic pipe and providing a fluid-tight connection in a high-pressure system, comprising:
a tubular plastic adapter unit having an open-ended bore at one end for telescoping with the non-metallic pipe, an internal annular shoulder facing toward the opening end of said bore, and a stepped internal passageway extending from said bore through the adapter unit to the opposite end thereof, said passageway comprising a first portion adjacent said opposite end having a first internal annular shoulder at its inner end spaced inwardly from said opposite end, a second portion smaller than said first portion having a second internal shoulder at its inner end, and a third portion smaller than said second portion between said second shoulder and said bore, and a ridge projecting inwardly from the wall of said passageway where said third portion meets said bore;
and a tubular metal insert disposed in said passageway and having an internally threaded end portion fitted in said first portion of said passageway and having an external shoulder pressing against said first internal shoulder, an elongated cylindrical end portion extending through said second and third portions of said passageway to said ridge, and an outwardly flared end of said cylindrical portion within said bore curving around said ridge and pressing against the ridge to lock the insert within the adapter unit;
an o-ring seal encircling said cylindrical end portion and positioned within said second portion of said passageway between said external shoulder and said second internal shoulder to form a fluid seal between said adapter unit and said insert;
and interfitting longitudinal keying means on the wall of said passageway within said third portion and on said end portion for preventing relative rotational movement of said adapter unit and said insert.
a tubular plastic adapter unit having an open-ended bore at one end for telescoping with the non-metallic pipe, an internal annular shoulder facing toward the opening end of said bore, and a stepped internal passageway extending from said bore through the adapter unit to the opposite end thereof, said passageway comprising a first portion adjacent said opposite end having a first internal annular shoulder at its inner end spaced inwardly from said opposite end, a second portion smaller than said first portion having a second internal shoulder at its inner end, and a third portion smaller than said second portion between said second shoulder and said bore, and a ridge projecting inwardly from the wall of said passageway where said third portion meets said bore;
and a tubular metal insert disposed in said passageway and having an internally threaded end portion fitted in said first portion of said passageway and having an external shoulder pressing against said first internal shoulder, an elongated cylindrical end portion extending through said second and third portions of said passageway to said ridge, and an outwardly flared end of said cylindrical portion within said bore curving around said ridge and pressing against the ridge to lock the insert within the adapter unit;
an o-ring seal encircling said cylindrical end portion and positioned within said second portion of said passageway between said external shoulder and said second internal shoulder to form a fluid seal between said adapter unit and said insert;
and interfitting longitudinal keying means on the wall of said passageway within said third portion and on said end portion for preventing relative rotational movement of said adapter unit and said insert.
2. An adapter as defined in claim 1 wherein the inner surface of said ridge is formed with a radius, and said outwardly flared end of said insert is a continuous surface formed and pressing against said radius to clamp said insert tightly into said adapter unit to provide a leak-tight connection.
3. An adapter as defined in claim 1 wherein said adapter unit is composed of high impact resistant plastic and said insert is composed of brass.
4. An adapter as defined in claim 1 wherein said keying means are closely interfitting longitudinal teeth around both the wall of said passageway and the exterior of said cylindrical end portion.
5. An adapter as defined in claim 1 wherein said opposite end portion of said adapter unit terminates in a narrow end surface, and said insert projects outwardly beyond said end surface and has an additional external shoulder abutting against the end surface.
6. An adapter for connecting a metal element to a non-metallic pipe, comprising:
a tubular plastic adapter unit having an open-ended bore at one end for connection to the non-metallic pipe and an internal passageway extending from said bore through said adapter unit to the opposite end thereof, said passageway having an enlarged end portion and at least one internal shoulder facing away from said bore;
and an inwardly projecting plastic ridge in said passageway at its junction with said bore having an inner surface formed with a radius;
and a tubular metal insert disposed in said passageway and having an end portion fitted in said enlarged end portion, an external shoulder pressing against the internal shoulder in said passageway, an elongated cylindrical portion extending past said ridge to said bore, and a flared inner end curved outwardly around the radius on said ridge, said flared inner end pressing against said ridge to hold said shoulders tightly together.
a tubular plastic adapter unit having an open-ended bore at one end for connection to the non-metallic pipe and an internal passageway extending from said bore through said adapter unit to the opposite end thereof, said passageway having an enlarged end portion and at least one internal shoulder facing away from said bore;
and an inwardly projecting plastic ridge in said passageway at its junction with said bore having an inner surface formed with a radius;
and a tubular metal insert disposed in said passageway and having an end portion fitted in said enlarged end portion, an external shoulder pressing against the internal shoulder in said passageway, an elongated cylindrical portion extending past said ridge to said bore, and a flared inner end curved outwardly around the radius on said ridge, said flared inner end pressing against said ridge to hold said shoulders tightly together.
7. An adapter as defined in claim 5 further including sealing means in said passageway between said external shoulder and said ridge.
8. An adapter as defined in claim 6 further including keying means acting between said cylindrical portion and said passageway to prevent relative rotation of the adapter unit and the insert.
9. An adapter for connecting a metal element to a non-metallic pipe, comprising:
a tubular non-metallic adapter unit having an open-ended bore at one end for connection to the non-metallic pipe and an internal passageway having an inner end opening into said bore, and extending from said bore through said adapter unit to the opposite end thereof, said passageway having at least one internal shoulder facing toward said opposite end, and said bore being larger than said passageway to form a second shoulder around said inner end facing toward said one end;
and a tubular metal insert disposed in said passageway and having an external shoulder pressing against said internal shoulder, an elongated cylindrical portion extending past said inner end of said passageway into said bore, and a flared inner end on said cylindrical portion curving outwardly into said recess and pressing against said adapter unit to draw said insert tightly into said adapter unit.
a tubular non-metallic adapter unit having an open-ended bore at one end for connection to the non-metallic pipe and an internal passageway having an inner end opening into said bore, and extending from said bore through said adapter unit to the opposite end thereof, said passageway having at least one internal shoulder facing toward said opposite end, and said bore being larger than said passageway to form a second shoulder around said inner end facing toward said one end;
and a tubular metal insert disposed in said passageway and having an external shoulder pressing against said internal shoulder, an elongated cylindrical portion extending past said inner end of said passageway into said bore, and a flared inner end on said cylindrical portion curving outwardly into said recess and pressing against said adapter unit to draw said insert tightly into said adapter unit.
10. An adapter as defined in claim 9 wherein said passageway has a second internal shoulder around said cylindrical portion and spaced from said external shoulder, and further including seal means pressed between said external shoulder and said second internal shoulder and sealing said passageway.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US4333287A | 1987-04-28 | 1987-04-28 | |
| US043,332 | 1987-04-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1309119C true CA1309119C (en) | 1992-10-20 |
Family
ID=21926631
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000565231A Expired - Lifetime CA1309119C (en) | 1987-04-28 | 1988-04-27 | Adapter for plastic pipe |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1309119C (en) |
-
1988
- 1988-04-27 CA CA000565231A patent/CA1309119C/en not_active Expired - Lifetime
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| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |