CA2025774A1 - Coupling for corrugated tubing - Google Patents
Coupling for corrugated tubingInfo
- Publication number
- CA2025774A1 CA2025774A1 CA 2025774 CA2025774A CA2025774A1 CA 2025774 A1 CA2025774 A1 CA 2025774A1 CA 2025774 CA2025774 CA 2025774 CA 2025774 A CA2025774 A CA 2025774A CA 2025774 A1 CA2025774 A1 CA 2025774A1
- Authority
- CA
- Canada
- Prior art keywords
- chamber
- conduit
- pair
- wall
- side wall
- 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.)
- Abandoned
Links
Landscapes
- Quick-Acting Or Multi-Walled Pipe Joints (AREA)
Abstract
COUPLING FOR CORRUGATED TUBING
ABSTRACT OF THE DISCLOSURE
A molded plastic fitting for joining the ends of corrugated non-metallic conduit includes a chamber having an open end for receiving the end of the conduit with locking tabs joined to the peripheral wall of the chamber and extending into the chamber in a direction axially away from the open end. The tabs terminate in a distal end arranged to latch between adjacent corrugations on the end of the conduit to maintain the conduit in the chamber. The peripheral side wall of the chamber is circumferentially continuous and of generally uniform thickness about the open end with a first pair of diametrically opposed sections of the side wall being spaced and configured to closely engage and guide the exterior of the conduit during its entry into the chamber. A second pair of diametrically opposed sections of the side wall are integrally joined to the first pair circumferentially intermediate thereof by smooth transition wall sections. The second pair are spaced and configured to lie radially outward of the conduit a substantial distance. The locking tabs have their base portions integral with and carried by the second pair of wall sections with an elongated body of each locking tab being relatively rigid but having a thin flexible pivot section at the base portion.
ABSTRACT OF THE DISCLOSURE
A molded plastic fitting for joining the ends of corrugated non-metallic conduit includes a chamber having an open end for receiving the end of the conduit with locking tabs joined to the peripheral wall of the chamber and extending into the chamber in a direction axially away from the open end. The tabs terminate in a distal end arranged to latch between adjacent corrugations on the end of the conduit to maintain the conduit in the chamber. The peripheral side wall of the chamber is circumferentially continuous and of generally uniform thickness about the open end with a first pair of diametrically opposed sections of the side wall being spaced and configured to closely engage and guide the exterior of the conduit during its entry into the chamber. A second pair of diametrically opposed sections of the side wall are integrally joined to the first pair circumferentially intermediate thereof by smooth transition wall sections. The second pair are spaced and configured to lie radially outward of the conduit a substantial distance. The locking tabs have their base portions integral with and carried by the second pair of wall sections with an elongated body of each locking tab being relatively rigid but having a thin flexible pivot section at the base portion.
Description
~OUPLIN~ FOR CORRU~ATBD TV~IN~
BACKGROUND OF THE INVENTION
The sub~ect lnvention 1~ directed toward the art of tube couplings and, more partloularly, to a molded, pla~tlc coupllng especlally suited for ~olning corrugated plasti¢
tubing.
The lnventlon wlll be described with reference to use of the coupling on a particular type of fittlngs however, as will become apparent, the coupling could be used on a varlety of types of fittings or formed as an lntegral part of various structures such as switch boxes, ~unction boxes and the like.
Many dlfferent snap-in or push-in type couplings have been proposed for use with corrugated plastlc pipe and tubing. One typical prior art coupling comprises an open ended cylindrical coupling body with the interior of the body sized to closely receive the exterior of the corrugated tubing. Inwardly extending tabs or fingers are carried within the body and lnclude end portlons which enter the recesses between adjacent corrugations to latch into the tubing and prevent its withdrawal. Couplings employing this general arrangement are illustrated, for example, in U.S.
patents 4,441,745: 4,575,133 and, 4,711,472.
one of the problems with these prior couplings has been that their design, primarily their geometry, results in inherent strength lim~tations. That is, their ability to reaist tublng wlthdrawal is somewhat more limited than would be desirable. Applicants' have found that these limitations result because the latching tabs or fingers have their polnt of primary pivoting or flexing in the cylindrical wall of the coupling body substantially at the outer diameter or surface of the tubing. As a aonsequence, the pivot point and the point at ~hich load is applied to the finger a~e nearly in alignment in the direction of the tubing pull-out force.
:
202~ 7~4 This result~ in a 60mewhat unstable latching condition. In fact, it is similar to an over center mechanism at or near its center position where a small lateral movement causes ~t to go over center. In the prior art type coupling a similar but undesirable result can take place when the end of the finger or the slde of the engaged corrugation deform~
slightly.
BRIEF STAT~MENT OF ~HE INVENTION
The ~ub~ect inventlon overcomes the noted problems and provides a coupling structure wherein the latch fingers are oriented and shaped to produce an improved latching geo~etry and increased 6trength. More particularly, the invention provides a connector fitting for ~oining to the end of non-metallic conduit of circular cross section having alternating circumferential protrusions and recesses. The connector fitting of the invention comprises a sleeve formed from pla~tlc and encloslng an inter10r chamber defined by a continuous peripheral s~de wall of substantially uniform thickness. The sleeve has an axial~y opened outer end sized for receiving the end of the non-metalllc conduit. A stop surface is located in the sleeve axially inwardly of the open end for limiting the inward extent of movement of the end of the condult. The peripheral ~ide wall includes a first pair of wall sections located in dlametrically opposed relationship extending axially inward of the interior chamber from the open end. The first pair of wall Bection8 i8 spaced and conflgured to closely engage and guide the end of the conduit as it enters;the chamber. A ~econd pair of wall~
~eotlons compl~tes the peripheral slde wall at least in the area ad~acent the open end. The second pair of wall sections 1B located in diametrically oppo6ed relationship clrcumf~rentially lntermediate the f1rst palr of wall - `- 202~77~
gections. The first and second wall ~eations are integrally connected by transition sectlon~ and the second pair is located such that they are spaced radially outwardly a substantial distance from the exterlor of the end of the conduit when it i8 in the chamber. ~ resilient latch tab having a thickness substantially equal to the thickness of the wall sections is carried by each of the second wall sections and is formed integrally therewith. The tabs have base portlon~ arranged for flexure at the radius of the second wall sections and the body of each of the tabs is inclined to extend axially and radially into the chamber and terminate in a free end located to extend into and latch in a recess on the end of a conduit received in the chamber.
Preferably, and in accordance wlth a more specific aspect of the invention the ends of the latch tabs are located in a plane which extends generally perpendicular to the axis of the interior chamber. Additionally, they have thelr free end radially inward of the flrst palr of wall sections.
Because of the arrangement of the second wall sections and the fact that the latch tab~ extend inwardly therefrom, the latch tabs pivot about a point or axis which is located a substantial distance radially outward from the tubing.
This provides a much more positive gripping relationship and assures that the tubing wil~ be held tightly and that attempted movement will produce an increasing gripping reaction between the latch tabs and the tubing.
~ecause of the defined relationship between the wall sections, together with their uniform thicXness, the coupling is extremely rigid and is not weakened or structurally compromised by the positioning of the tab~
Accordingly, the primary ob~ect of the invention is the provision of a molded plastic connector for corrugated tubing wherein an extremely advantageous relationship between the locklng tabs and the corrugated tubing results because of the exterior design and mounting of the tabs.
, . . .:- :- . ~ :
~ 2 ~ 7 ~ ~ r~
Yet another ob~ect of the invention i~ the provision of a molded pla~tlc coupling of the type described wherein the coupling ha~ a somewhat elliptical body shape to most desirably po~it~on the tabs relative to the tubing.
A still further ob~ect is the provision of a corrugated tube coup~lng design where~n attempted withdrawal of the tublng results ln an lncreased locking force belng generated by the locking tabs.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other ob~ects and advantage~ will become apparent from the following description when read in con~unction with the accompanying drawings wherein:
FIGURE l is a pictorial view of a fitting lncorporating a corrugated tube coupllng formed in accordance with the sub~ect invention:
FIGURE 2 i~ an end vlew of the right hand end of the :
fitting shown in FIGURE l;
FIGURE 3 i8 a cros~-sectional view taken on line 3 3 of FIGURE 2;
FIGURE 4 is a view slmilar to FIGURE 3 but showing a corrugated tubing end in assembled position in the fitting:
FIGURE 5 iB a greatly enlarged view of the circled area of FIGURE 4: and, FIGU~E 6 is a view taken on line 6-6 of FIGURE 2.
~5 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referrlng more particularly to the drawing~ where the showings àre for thei purpooe of iIlustrating a preferred embodlment of the invention only, and not for the purpose of limiting ~ame, FIGURES I through 3 show the overall arrangement of a molded, one-piece plastic fitting 10 designed to ~oin corrugated plastlc tubing to a panel member or ~unction box assembly. The fitting 10 is merely one form : :~
of fitting in which the coupllng of the sub~ect invention could be utllized. That l~, the improved coupling portion :
` 2~2~7~'~
of the fitting 10 could be formed on other types of fittings or integrally with ewitch boxe~, junction boxes or the like.
In thi~ embodiment, fitting 10 comprises a first cylindrlcal end portlon 12 which is provided wlth exterlor threads 14 that allow the end portion 12 to extend through a preformed openlng ln a panel or ~unctlon box wall and be connected thereto through the use of a sultable nut received on the threads 14. A panel 16 and a sultable connectlng nut lB are shown in phantom in FIGURE 3.
lo The rlght hand end of fittlng lo ~as vlewed ln FIGURES
1 and 2) defines the improved coupling portion and comprises a somewhat enlarged sleeve sectlon 20 which is forme~
integrally wlth section 12 and connects therewith by a radial wall portlon 22. As best seen in FIGURE 3, sleeve sectlon 20 define~ an interior chamber 24 which ha~ lts rlght hand end open to define a mouth or entrance for receipt of corrugated tubing in a manner ~ubsequently to be described.
The left hand end of chamber 24 ~oins to a central passage-way 26 formed through section 12.
The sleeve portion 20 is deflned by a first pair of radially oppo~ed wall section~ 28 which each have a ~ ~", circumferential extent of approximately 90 degrees as best seen in FIGURE 2. The wall sections 28 preferably have a thickness T which is generally uniform throughout their circumferential extent. The interior wall surface 28A of the wall sections 28 i9 located at a radial distance R~ from the axis of the coupling. This radius Rl is only slightly larger than the maximum exterior radius on the tubing which is to be ~oined in the coupling. This allows the lnterior surfaces 28A to act as guide surfaces for closely engaging about the exterior of the corrugated tubing to guide and hold it properly located in the chamber 24. -~
The sleeve 20 further includes a second pair of opposea wall sections 30 which are located circumferentially lntermediate the wall sections 28 on dlametrically opposed sides of the chamber 24. Wall sections 30 hava a thickness ~ ~ 2~7~
T2 which iB substantially equally to thickness r,. It is important to note that wall sections 30 are dlsplaced radially outward from the location of wall sectlons 28 and are ~olned to wall ~ectlon~ 28 by tran~ltlon sectlon~ 32.
According to the invention, the wall sections 30 are preferably displaced radlally outward relatlve to the wall sectlons 28 by a distance whlch is approxlmately equal to wall thickness Tl. As best lllustrated ln FIGURE 2, the radlus R2 is approximately at least equal to the 6um of radlus R~ plu~ Tl. The lmportance of this relatlonshlp will subsequently become apparent.
As best shown in FIGURES 3 and 4, the axlally lnnermost end of the chamber 24 i8 of uniform dlameter throughout lts circumferential extent and is located at radlus Rl. Thus, the lnnermost end of the tubing 18 gulded throughout its circumferential extent and 18 prevented from havlng any appreclable radial freedom of movement.
FIGURE 4 shows the fitting 10 wlth a section of tubing 36 positloned therein. As lllustrated, the lnner end of the tublng engages with the radlal wall 22 to provide an axial llmlt to movement and positioning.
The tubing 36 18 maintained locked in the assembled posltlon lllustrated ln FIGURE 4 by a palr of relatively rigid latch tab members 40 which axe carried from the opposed wall 8ections 30 as lllustrated. A8 best shown in FIGURE 6, each of the wall sections 40 is centrally po~itloned from the assoclated wall sectlon 30 and extends radially and axially into the chamber 24. A generally C-shaped opening 42 ls formed aboùt each o`f the latch tabs 40 so that the tabs can move freely ln a radial direction. The latch tabs 40 extend axially and radially lnward and termlnate ln a free end portion 42 which has an end face 44 (see FIGURE 5) which preferably lles ln a plane perpendicular to the longitudinal axis of flttlng 10. Preferably, each of the latch fingers 40 has a thlckness which is as greàt or greater than the thlckness Tl of the wall sectlon 28. Addltionally, the inner :
- - ` 2~77~
surface of each latch tab 40 i~ preferably inclined at a first angle A which is in the range of 15 to 25 degrees and a second angle B which is ln the range of 45 to 50 degree~, as best seen in FIGURE 3. The lncline is designed so that as the corrugated tublng is moved lnto the chamber 24 the latch tabs 40 are cammed radially outward until the tublng 3 6 i8 in the located position shown in FIGURE 4. At this time the inner dlstal end~ of the latch tabs 40 enter between ad~acent corrugation~ to lock th~ tublng in the position lo shown. In order to assure the proper pivoting of the tabs and allow manual in~ertion of the tubing 36 into the fitting a relief groove or the like 46 can be formed along the base of each latch tab 40. This results in a thinning of the material in this area so that greater flexiblllty of the pivot area of associatea latch tab is provided.
As can readily be seen from FIGURE 5 the sub~ect arrangement assures that the pivot point "P" for the latch tabs 40 ls located radially outward a substantial di6tance relative to the point of applicatlon of forces to the latch tab by the tubing. This produces a distinct latching effect for each latch tab and assures a radially inward directed movement of the latch tab to more tightly grip the tubing if an attempt is made to withdrawal the tubing from the fitting.
In addition, the shape of the latch tab resulting from the arrangement of the lnternal surface~ provides a greatly strengthened latch tab in the area of greatest force appllcation. This provides a very rigid tab body and ~ ~ ~
prevents collapse of the body during force application. ` ~ ~ ;
The invention has~ been de~cribed in great detail sufficient to enable one of ordinary skill in the art to make and U8Q the same. obviously, modifications and alterations of preferred embodiment wlll occur to others upon the reading and understanding of the sub~ects ~pecifications and it is our intention to include all such modifications and ~ -alteratlons as part of our invention insofar as they come within the scope of the appended claims. - ,~
.
BACKGROUND OF THE INVENTION
The sub~ect lnvention 1~ directed toward the art of tube couplings and, more partloularly, to a molded, pla~tlc coupllng especlally suited for ~olning corrugated plasti¢
tubing.
The lnventlon wlll be described with reference to use of the coupling on a particular type of fittlngs however, as will become apparent, the coupling could be used on a varlety of types of fittings or formed as an lntegral part of various structures such as switch boxes, ~unction boxes and the like.
Many dlfferent snap-in or push-in type couplings have been proposed for use with corrugated plastlc pipe and tubing. One typical prior art coupling comprises an open ended cylindrical coupling body with the interior of the body sized to closely receive the exterior of the corrugated tubing. Inwardly extending tabs or fingers are carried within the body and lnclude end portlons which enter the recesses between adjacent corrugations to latch into the tubing and prevent its withdrawal. Couplings employing this general arrangement are illustrated, for example, in U.S.
patents 4,441,745: 4,575,133 and, 4,711,472.
one of the problems with these prior couplings has been that their design, primarily their geometry, results in inherent strength lim~tations. That is, their ability to reaist tublng wlthdrawal is somewhat more limited than would be desirable. Applicants' have found that these limitations result because the latching tabs or fingers have their polnt of primary pivoting or flexing in the cylindrical wall of the coupling body substantially at the outer diameter or surface of the tubing. As a aonsequence, the pivot point and the point at ~hich load is applied to the finger a~e nearly in alignment in the direction of the tubing pull-out force.
:
202~ 7~4 This result~ in a 60mewhat unstable latching condition. In fact, it is similar to an over center mechanism at or near its center position where a small lateral movement causes ~t to go over center. In the prior art type coupling a similar but undesirable result can take place when the end of the finger or the slde of the engaged corrugation deform~
slightly.
BRIEF STAT~MENT OF ~HE INVENTION
The ~ub~ect inventlon overcomes the noted problems and provides a coupling structure wherein the latch fingers are oriented and shaped to produce an improved latching geo~etry and increased 6trength. More particularly, the invention provides a connector fitting for ~oining to the end of non-metallic conduit of circular cross section having alternating circumferential protrusions and recesses. The connector fitting of the invention comprises a sleeve formed from pla~tlc and encloslng an inter10r chamber defined by a continuous peripheral s~de wall of substantially uniform thickness. The sleeve has an axial~y opened outer end sized for receiving the end of the non-metalllc conduit. A stop surface is located in the sleeve axially inwardly of the open end for limiting the inward extent of movement of the end of the condult. The peripheral ~ide wall includes a first pair of wall sections located in dlametrically opposed relationship extending axially inward of the interior chamber from the open end. The first pair of wall Bection8 i8 spaced and conflgured to closely engage and guide the end of the conduit as it enters;the chamber. A ~econd pair of wall~
~eotlons compl~tes the peripheral slde wall at least in the area ad~acent the open end. The second pair of wall sections 1B located in diametrically oppo6ed relationship clrcumf~rentially lntermediate the f1rst palr of wall - `- 202~77~
gections. The first and second wall ~eations are integrally connected by transition sectlon~ and the second pair is located such that they are spaced radially outwardly a substantial distance from the exterlor of the end of the conduit when it i8 in the chamber. ~ resilient latch tab having a thickness substantially equal to the thickness of the wall sections is carried by each of the second wall sections and is formed integrally therewith. The tabs have base portlon~ arranged for flexure at the radius of the second wall sections and the body of each of the tabs is inclined to extend axially and radially into the chamber and terminate in a free end located to extend into and latch in a recess on the end of a conduit received in the chamber.
Preferably, and in accordance wlth a more specific aspect of the invention the ends of the latch tabs are located in a plane which extends generally perpendicular to the axis of the interior chamber. Additionally, they have thelr free end radially inward of the flrst palr of wall sections.
Because of the arrangement of the second wall sections and the fact that the latch tab~ extend inwardly therefrom, the latch tabs pivot about a point or axis which is located a substantial distance radially outward from the tubing.
This provides a much more positive gripping relationship and assures that the tubing wil~ be held tightly and that attempted movement will produce an increasing gripping reaction between the latch tabs and the tubing.
~ecause of the defined relationship between the wall sections, together with their uniform thicXness, the coupling is extremely rigid and is not weakened or structurally compromised by the positioning of the tab~
Accordingly, the primary ob~ect of the invention is the provision of a molded plastic connector for corrugated tubing wherein an extremely advantageous relationship between the locklng tabs and the corrugated tubing results because of the exterior design and mounting of the tabs.
, . . .:- :- . ~ :
~ 2 ~ 7 ~ ~ r~
Yet another ob~ect of the invention i~ the provision of a molded pla~tlc coupling of the type described wherein the coupling ha~ a somewhat elliptical body shape to most desirably po~it~on the tabs relative to the tubing.
A still further ob~ect is the provision of a corrugated tube coup~lng design where~n attempted withdrawal of the tublng results ln an lncreased locking force belng generated by the locking tabs.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other ob~ects and advantage~ will become apparent from the following description when read in con~unction with the accompanying drawings wherein:
FIGURE l is a pictorial view of a fitting lncorporating a corrugated tube coupllng formed in accordance with the sub~ect invention:
FIGURE 2 i~ an end vlew of the right hand end of the :
fitting shown in FIGURE l;
FIGURE 3 i8 a cros~-sectional view taken on line 3 3 of FIGURE 2;
FIGURE 4 is a view slmilar to FIGURE 3 but showing a corrugated tubing end in assembled position in the fitting:
FIGURE 5 iB a greatly enlarged view of the circled area of FIGURE 4: and, FIGU~E 6 is a view taken on line 6-6 of FIGURE 2.
~5 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referrlng more particularly to the drawing~ where the showings àre for thei purpooe of iIlustrating a preferred embodlment of the invention only, and not for the purpose of limiting ~ame, FIGURES I through 3 show the overall arrangement of a molded, one-piece plastic fitting 10 designed to ~oin corrugated plastlc tubing to a panel member or ~unction box assembly. The fitting 10 is merely one form : :~
of fitting in which the coupllng of the sub~ect invention could be utllized. That l~, the improved coupling portion :
` 2~2~7~'~
of the fitting 10 could be formed on other types of fittings or integrally with ewitch boxe~, junction boxes or the like.
In thi~ embodiment, fitting 10 comprises a first cylindrlcal end portlon 12 which is provided wlth exterlor threads 14 that allow the end portion 12 to extend through a preformed openlng ln a panel or ~unctlon box wall and be connected thereto through the use of a sultable nut received on the threads 14. A panel 16 and a sultable connectlng nut lB are shown in phantom in FIGURE 3.
lo The rlght hand end of fittlng lo ~as vlewed ln FIGURES
1 and 2) defines the improved coupling portion and comprises a somewhat enlarged sleeve sectlon 20 which is forme~
integrally wlth section 12 and connects therewith by a radial wall portlon 22. As best seen in FIGURE 3, sleeve sectlon 20 define~ an interior chamber 24 which ha~ lts rlght hand end open to define a mouth or entrance for receipt of corrugated tubing in a manner ~ubsequently to be described.
The left hand end of chamber 24 ~oins to a central passage-way 26 formed through section 12.
The sleeve portion 20 is deflned by a first pair of radially oppo~ed wall section~ 28 which each have a ~ ~", circumferential extent of approximately 90 degrees as best seen in FIGURE 2. The wall sections 28 preferably have a thickness T which is generally uniform throughout their circumferential extent. The interior wall surface 28A of the wall sections 28 i9 located at a radial distance R~ from the axis of the coupling. This radius Rl is only slightly larger than the maximum exterior radius on the tubing which is to be ~oined in the coupling. This allows the lnterior surfaces 28A to act as guide surfaces for closely engaging about the exterior of the corrugated tubing to guide and hold it properly located in the chamber 24. -~
The sleeve 20 further includes a second pair of opposea wall sections 30 which are located circumferentially lntermediate the wall sections 28 on dlametrically opposed sides of the chamber 24. Wall sections 30 hava a thickness ~ ~ 2~7~
T2 which iB substantially equally to thickness r,. It is important to note that wall sections 30 are dlsplaced radially outward from the location of wall sectlons 28 and are ~olned to wall ~ectlon~ 28 by tran~ltlon sectlon~ 32.
According to the invention, the wall sections 30 are preferably displaced radlally outward relatlve to the wall sectlons 28 by a distance whlch is approxlmately equal to wall thickness Tl. As best lllustrated ln FIGURE 2, the radlus R2 is approximately at least equal to the 6um of radlus R~ plu~ Tl. The lmportance of this relatlonshlp will subsequently become apparent.
As best shown in FIGURES 3 and 4, the axlally lnnermost end of the chamber 24 i8 of uniform dlameter throughout lts circumferential extent and is located at radlus Rl. Thus, the lnnermost end of the tubing 18 gulded throughout its circumferential extent and 18 prevented from havlng any appreclable radial freedom of movement.
FIGURE 4 shows the fitting 10 wlth a section of tubing 36 positloned therein. As lllustrated, the lnner end of the tublng engages with the radlal wall 22 to provide an axial llmlt to movement and positioning.
The tubing 36 18 maintained locked in the assembled posltlon lllustrated ln FIGURE 4 by a palr of relatively rigid latch tab members 40 which axe carried from the opposed wall 8ections 30 as lllustrated. A8 best shown in FIGURE 6, each of the wall sections 40 is centrally po~itloned from the assoclated wall sectlon 30 and extends radially and axially into the chamber 24. A generally C-shaped opening 42 ls formed aboùt each o`f the latch tabs 40 so that the tabs can move freely ln a radial direction. The latch tabs 40 extend axially and radially lnward and termlnate ln a free end portion 42 which has an end face 44 (see FIGURE 5) which preferably lles ln a plane perpendicular to the longitudinal axis of flttlng 10. Preferably, each of the latch fingers 40 has a thlckness which is as greàt or greater than the thlckness Tl of the wall sectlon 28. Addltionally, the inner :
- - ` 2~77~
surface of each latch tab 40 i~ preferably inclined at a first angle A which is in the range of 15 to 25 degrees and a second angle B which is ln the range of 45 to 50 degree~, as best seen in FIGURE 3. The lncline is designed so that as the corrugated tublng is moved lnto the chamber 24 the latch tabs 40 are cammed radially outward until the tublng 3 6 i8 in the located position shown in FIGURE 4. At this time the inner dlstal end~ of the latch tabs 40 enter between ad~acent corrugation~ to lock th~ tublng in the position lo shown. In order to assure the proper pivoting of the tabs and allow manual in~ertion of the tubing 36 into the fitting a relief groove or the like 46 can be formed along the base of each latch tab 40. This results in a thinning of the material in this area so that greater flexiblllty of the pivot area of associatea latch tab is provided.
As can readily be seen from FIGURE 5 the sub~ect arrangement assures that the pivot point "P" for the latch tabs 40 ls located radially outward a substantial di6tance relative to the point of applicatlon of forces to the latch tab by the tubing. This produces a distinct latching effect for each latch tab and assures a radially inward directed movement of the latch tab to more tightly grip the tubing if an attempt is made to withdrawal the tubing from the fitting.
In addition, the shape of the latch tab resulting from the arrangement of the lnternal surface~ provides a greatly strengthened latch tab in the area of greatest force appllcation. This provides a very rigid tab body and ~ ~ ~
prevents collapse of the body during force application. ` ~ ~ ;
The invention has~ been de~cribed in great detail sufficient to enable one of ordinary skill in the art to make and U8Q the same. obviously, modifications and alterations of preferred embodiment wlll occur to others upon the reading and understanding of the sub~ects ~pecifications and it is our intention to include all such modifications and ~ -alteratlons as part of our invention insofar as they come within the scope of the appended claims. - ,~
.
Claims (9)
1. A connector fitting for joining to the end of non-metallic conduit of circular cross-section having alternating annular protrusions and recesses, the connector fitting comprising:
a sleeve formed from plastic and enclosing an interior chamber defined by a continuous peripheral side wall of substantially uniform thickness, said sleeve having an axially open outer end sized for receiving the end of the non-metallic conduit in said interior chamber;
a stop surface located in said sleeve axially inwardly of said open end for limiting the inward extent of movement of the end of said conduit;
said peripheral side wall having a first pair of wall sections located in diametrically opposed relationship extending axially inward of said interior chamber from said open end, said first pair of wall sections being spaced and configured to closely engage and guide the end of said conduit as it enters said chamber;
said peripheral side wall having a second pair of wall sections located in diametrically opposed relationship circumferentially intermediate said first pair of wall sections, said second pair of wall sections being integrally connected with said first pair of wall sections and located such that they are spaced radially outward a substantial distance from the exterior of the end of said conduit when it is in said chamber; and, each of said second wall sections carrying a rigid latch tab which is formed integrally therewith and is inclined to axially and radially into said chamber, each latch tab including a flexible pivot portion is the second wall section and terminating in a free end located to extend into and latch in a recess on the end of a conduit received in said chamber.
a sleeve formed from plastic and enclosing an interior chamber defined by a continuous peripheral side wall of substantially uniform thickness, said sleeve having an axially open outer end sized for receiving the end of the non-metallic conduit in said interior chamber;
a stop surface located in said sleeve axially inwardly of said open end for limiting the inward extent of movement of the end of said conduit;
said peripheral side wall having a first pair of wall sections located in diametrically opposed relationship extending axially inward of said interior chamber from said open end, said first pair of wall sections being spaced and configured to closely engage and guide the end of said conduit as it enters said chamber;
said peripheral side wall having a second pair of wall sections located in diametrically opposed relationship circumferentially intermediate said first pair of wall sections, said second pair of wall sections being integrally connected with said first pair of wall sections and located such that they are spaced radially outward a substantial distance from the exterior of the end of said conduit when it is in said chamber; and, each of said second wall sections carrying a rigid latch tab which is formed integrally therewith and is inclined to axially and radially into said chamber, each latch tab including a flexible pivot portion is the second wall section and terminating in a free end located to extend into and latch in a recess on the end of a conduit received in said chamber.
2. The connector fitting as defined in claim 1 wherein said first and second wall sections are joined by continuous smooth transition walls.
3. The connector fitting as defined in claim 1 wherein said sleeve includes an axially inner end portion remote from said open end, said inner end portion being cylindrical and sized to closely receive the end of the conduit received in said chamber.
4. The connector fitting as defined in claim 1 wherein said latch tabs have a relatively rigid main body with a radial thickness at least substantially equal to the thickness of said peripheral side wall.
5. The connector fitting as defined in claim 4 wherein said latch tabs terminate in free end faces which lie in a plane generally perpendicular to the axis of said sleeve.
6. In a molded plastic connector fitting for engaging and joining the ends of cylindrical corrugated non-metallic conduit and including a peripheral side wall which defines a chamber having an open end for receiving the end of said conduit with locking tabs having a base portion joined to said peripheral wall with an elongated body extending into said chamber in a direction axially away from the open end and terminating in a distal end to latch between adjacent corrugation on the end of said conduit to maintain said conduit in said chamber the improvement wherein:
said peripheral side wall is circumferentially continuous and of generally uniform thickness about said open end with a first pair of diametrically opposed sections of said side wall being spaced and configured to closely engage and guide the exterior of said conduit during its entry into said chambers a second pair of diametrically opposed sections of said side wall being integrally joined to said first pair circumferentially intermediate thereof by smooth transition wall sections, said second pair of wall sections is spaced and configured to lie radially outwardly of said conduit a substantial distance when said conduit is received in said chamber; and, said locking tabs having their base portions integral with and carried by said second pair of wall sections, said elongated body of each locking tab being relatively rigid but having a thin flexible pivot section at said base portion.
said peripheral side wall is circumferentially continuous and of generally uniform thickness about said open end with a first pair of diametrically opposed sections of said side wall being spaced and configured to closely engage and guide the exterior of said conduit during its entry into said chambers a second pair of diametrically opposed sections of said side wall being integrally joined to said first pair circumferentially intermediate thereof by smooth transition wall sections, said second pair of wall sections is spaced and configured to lie radially outwardly of said conduit a substantial distance when said conduit is received in said chamber; and, said locking tabs having their base portions integral with and carried by said second pair of wall sections, said elongated body of each locking tab being relatively rigid but having a thin flexible pivot section at said base portion.
7. The improved connector fitting as defined in claim 6 wherein said locking tabs are located at circumferentially spaced positions and the thickness of said elongated body of each locking tab is at least as great as the thickness of said peripheral side wall.
8. The improved connector fitting as defined in claim 6 wherein said locking tabs are arranged to extend inwardly into said chamber a distance such that their distal ends lie radially inwardly of the first pair of opposed sections of said side wall.
9. The improved connector fitting as defined in claim 8 wherein said tabs each have their respective distal ends located the same axial distance from the open end of said chamber.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US45932289A | 1989-12-29 | 1989-12-29 | |
| US459,322 | 1989-12-29 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2025774A1 true CA2025774A1 (en) | 1991-06-30 |
Family
ID=23824310
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2025774 Abandoned CA2025774A1 (en) | 1989-12-29 | 1990-09-20 | Coupling for corrugated tubing |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2025774A1 (en) |
-
1990
- 1990-09-20 CA CA 2025774 patent/CA2025774A1/en not_active Abandoned
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |