CA1070644A

CA1070644A - Torque-limiting device

Info

Publication number: CA1070644A
Application number: CA186,273A
Authority: CA
Inventors: Dawson Friend
Original assignee: Stant USA Corp
Current assignee: Stant USA Corp
Priority date: 1972-11-20
Filing date: 1973-11-20
Publication date: 1980-01-29
Also published as: DE2357789C3; US3820680A; DE2357789A1; DE2357789B2

Abstract

ABSTRACT OF THE DISCLOSURE
A cap for closing a chamber having a filler neck formed to provide an internal thread and a peripherally extending lip at its mouth, the cap comprising a housing which has a longitudinal axis and axially spaced outer and inner end portions and which is formed to provide, at its outer end portion, a radially outwardly extending flange and, extending axially inwardly from the flange, a shank with a mating external thread. A concentric sealing ring is disposed adjacent the flange for sealing engagement with the lip, and a shell covers at least the outer portion of the housing. The flange provides at least one resilient finger having a lug at its distal end, and the shell provides at least one pocket for receiving the lug and providing a torque limited driving connection in one sense of relative rotation between the shell and the housing.
This pocket is formed with camming surface at its trailing end as the shell is turned to advance the shank axially in-wardly and an abrupt surface at its leading end. The camming surface is effective to cam the lug out of the pocket when the limit of the torque limited driving connection is exceeded as the torque resistance to rotation of the housing in the said one sense exceeds a predetermined level.

Description

:
The present invention relates to caps, and more particularly .~;
` to the provision of closure caps which are threaded onto ~iller necks~ .
and which are provided with o-ring seals for sealing engagement with J, the lip of the necksO
The use of O-ring seals and other types of relatively soft, rubber-like or rubberoid gaskets to provide a seal between a closure cap and the mouth of a container presents a problem when the cap is to be removed and placed back on the neck frequently. The problem ~ i~ that the seal becomea damaged when excessive tightening torque 10 i8 applied to the cap. Others have heretofore attempted to solve this problem by providing torque-limiting devices for screw-on ,~, clo~ure caps.
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~` I believe that my torque-limiting device is a significant ,. .:
' improvement over the devices heretofore proposed.

A primary object of my invention is to provide a valved cap , ....
for closing an automobile gasoline tank, ~aid cap comprising a valve housing which threads into the filler neck and a shell which covers at least the outer portion of the valve housing with torque-limited ;~ means providing a driving connection between the shell and the housing in the direction which advances the housing into engagement ..
with the filler neck. An o-ring seal is carried by the housing for ,!,.
sealing engagement with the lip of the filler neck.
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Thus, in accordance with my present invention, the torque ..
which can be applied to tighten the housing and the sealing ring is ;` limited to a value which will not damage the sealing ring. Pre-ferably, the means which provides the driving connection between the shell and the valve housing provides a firm driving connection in ~- the direction which disengages the valve housing from the filler .., A
~`~ neck, i.e., which moves the sealing ring away from the mouth of the ','~
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filler neck.
According to the present invention there is provided a cap for closing a chamber having a filler neck which is provided with an internal thread and with a peripherally extending lip at its mouth, said cap comprising a housing having ,., a longitudinal axis and axially spaced outer and inner end portions said housing having, at said outer end portion thereof, a radially outwardly and peripherally extending flange and, extending axially inwardly from said flange, a shank with an external thread on the outer periphery thereof, for mating with the internal thread, said flange providing at least one finger which is resiliently movable in the direction of said longitudinal axic, the or each finger having an axially outwardly extending lug at its di~tal end, a concentric sealing ring disposed adjacent said flange for sealing engagement with such a lip, a shell covering at least said outer end portion of said housing, said shell providing at lea~t one axially inwardly opening pocket, with the or each lug being adapted to be received in the pocket or a re~pective one of the pockets, respectively, the or each pocket being formed with a camming surface at its trailing end relative to one sense of turning of the shell relative to the housing to provide a torgué limi~ed driving connection between the shell and the housing in said one sense of turning of the shell for advancing the shank into engagement with such a ;
.:. filler neck, and the or each pocket having an abrupt surface ....
at its leading end relative to said one sense of turning of the :~ shell with the or each camming surface being ef~ective to cam . the lug or the respective one of the lugs, respectively, out of ~ the pocket or the respective one of the pocket~, respectively, : ' ,' ~.
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when the limit of the torque limited driving connection between said shell and said housing i8 exceeded as the resistance to turning of said housing in said one sense exceeds a predetermined v~, level.
Other objects and features of the invention will become apparent as this description progresses.
To the accomplishment of the above and related objects, this invention may be embodied in the forms illustrated in the ;, :
accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that change , . . .
may be made in the specific constructions illustrated and de~cribed, 80 long as the scope of the appended claims is not violated.

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In the drawings:
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Fig. 1 is a plan view of a closure cap constructed in accordance with my present invention;
~-~ Fig. 2 is a sectional view taken from Fig. 1 generally . .:
along the lines 2-2;

~:; Yig. 3 is a fragmentary sectional view taken from Fig. 1 , .
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- 2a -generally along the lines 3-3;
Fig. 4 is a plan view of the preferably plastic housing mem~ex which provides the threaded shank which extends into the filler neck;
Fig. 5 is a fragmentary sectional view taken from FigO 4 generally along the lines 5-5;
Fig. 6 is a sectional view taken from Fig. 4 generally along the lines 6-6, and ~-; Fig. 7 is a fragmentary sectional view showing still another technique for connecting the shell to the housing.
, Referring now to the drawings, it will be seen that I have il-lustrated a filler neck indicated generally by the reference numeral 10 provided by a generally cylindrically-shaped shell 11 formed to provide, adjacent its outer end portion, an internal thread 12 and, ; at its outer portion, an outwardly turned lip 13. My cap, indicated .' generally by the reference numeral 14, for closing the filler neck 10 comprises a housing or housing member 16 formed to have, at its outer end portion, an outwardly and peripherally extending flange ,; ~ ..
17 and an axially inwardly extending shank 18 providing an external mating thread 19. The housing member 16 is also formed with a peri-pherally extending groove 20 adjacent the axially inner side of the flange 17 and in which is disposed an 0-ring 22 proportioned and ~- designed sealably to engage the lip 13 when the housing member is threaded into the filler neck to the position shown in Fig. 2.
(As best seen in Fig. 4, ~he flange 17 is formed with a pair of _~ _ ,. . . ... ... ...
oppositely disposed paripherally extending slots 23 providing peri-pherally extending spring-like ingers 23a carrying at their distal ` enas locking lugs 240 A metal shell 25 covers at least the outer portion of the housing member 16, this shell providing four periphe-- 3 ~

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107064~

rally spaced apart pockets 26 for receiving the lugs 24. AS Will . :
be more fully discussed hereinafter, the engagement of the lugs 24 in the pockets 26 provides a driving connection between the shell 25 and the housing member 16, which driving connection is torque-limited to prevent damaging the o-ring 22.
In the embodiment of Fig. 2, the shell 25 is formed to have a peripheral depending skirt 27, the inner portion 28 of which is turned in to capture the flange 17 within the shell. An ear 29 is riveted to the upper surface or outer surface of the shell 25 as indicated at 30 to provide means for turning the shell, thereby turning the housing member 16.
The shank 18 has a valved passageway extending axially there-through. ~he outer, larger portion of this passageway is indicated at 32. As best seen in Figs. 4 and 5, this passageway portion 32 i8 concentric and axially inwardly extending. The shank 18 provides i: ~
a peripherally and inwardly extending, outwardly facing annular ,.,~
seat 34 at the inner end of the pas~ageway portion 32, and, exten-, ding inwardly from the seat 34, a tapered portion 35 which terminates with an inwardly and peripherally extending spring seat 36 having a concentric vent opening 37 therein.

The outer end of the passageway portion 32 is provided with ..:
a rabbet 40. An insert 41 having a peripherally extending mounting flange 42 received in the rabbet 40 is provided, this insert having ., a ~hank portion 43 extending axially inwardly. The shank portion 43 provides, spaced outwardly from the seat 34, a concentric annular . .
inwardly facing seat 45 and a reduced portion 46 extending axially inwardly a short distance from the seat 45, this reduced shank portion 46 being provided with peripherally spaced apart, axially extending grooves as indicated at 47.
In the illustrative embodiment, the valve gasket means 49 : ~ - 10706~4 lncludes an annular, flexible gasket or diaphragm 49 formed to provide an outer, peripherally extending bead 50 in sealing engage-ment with the seat 34 and an inner peripherally extending bead 51 ; in sealing engagement with the seat 45.
A seal plate 54 is disposed between a vacuum spring 57 and the inner peripheral portion of the gasket 49. The vacuum spring 57 is a coiled compression spring acting between the seal plate 54 and the spring seat 36.
A seal plate 58 is disposed between the pressure spring 61 ; 10 and the outer peripheral portion of the gasket 49. The spring 61, which is a coiled compression spring, may be confined, at its upper end, in a concentric groove 62 formed in the mounting flange 42 of the insert 41.
The insert 41 is provided with a plurality of peripherally . spaced apart venting apertures 64. When pressure in the gasoline . .
tank closed by the cap 14 becomes excessive, the bead 50 moves away from the seat 34 to permit air and vapors to move about the bead and through the apertures 64 and over the top of the insert 41 as indicated by the arrows 6S. When an excessive vacuum con-. 20 dition exists in the tank, the bead Sl moves inwardly from theseat 45 to permit air to move past the bead 51, through the grooves .~ 47 and the aperture 37 into the tank.
: The two-way valve action just discussed is fully disclosed in our companion Canadian application No. 186,192, filed November 19, 1973.
In the embodiment of Fig. 2, the shell 25 is connected to the ~; housing 16 for rotation relative to the axis of the housing by the inturned portion 28 engaging the axially inner side of the flange 17. Other techniques, of course, may be used for connecting the _ 5 .~..;
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-` ~ 10'7069~
shell 25 to the housing 16. In Fig. 6, an outer peripheral portion of the shell 25 is shown having an enlarged inner skirt portion 28a which may be formed to have a plurality of radially inwardly ex-tending indentations such as indicated at 70 to capture an annular flat ring 71 against the axially inner side of the flange 17. In Fig. 7, there is shown a portion of the shell 25 which has an en-larged inner skirt portion 28b turned in as indicated at 28c to capture an annular angle bracket 72 having a radially and periphera-` lly extending flange 73 which engages the axially inner side of the flange 17. Thus, in the illustrative en~bodiments, the shell 25 includes means engaging the axially inner side of the flange 17 to connect the shell to the housing 16 for relative rotation about the axis of the housing.
Thus, the dimension between the axially outer surface 75 and the axially inner surface 76 of the flange 17 is a control dimension such that the combined axial thickness of the distal end portion of each Linger 23a and the lug 24 at its distal end must not be subs-; tantially greater than the thickness of the flange 17 because the lug must move relatively freely from pocket 26 to pocket 26 in the shell 25. As best seen in Figs. 3, 5 and 6, the axially inner side of each finger 23a inclines axially outwardly from its proximal end to its distal end as indicated at 77. This tapering will permit the lug 24 to be calmned inwardly (downwardly in Figs. 3, 5 and 6) so that it will not protrude axially outwardly from the side 75 of the flange 17.
The lug 24, in the illustrative embodiment, is generally rec-tangularly shaped having abrupt, axially extending trailing and leading edges 78J 79. The radially inner and outer surfaces 80, 81 of each lug are peripherally extending to follow the curvatures of - 6_ ,. .

,~ 1070644 slits 23 and the outer peripheral edge of the flange 17 as best seen in Fig. 4.
Each pocket 26 is formed with a camming surface 82 at its trailing edge as the shell 25 is turned in the direction which ad-vances the thread 19 into engagement with the thread 12, i.e., the clockwise direction as viewed in Fig. 1. The leading edge or end of the pocket 26 is an abrupt, axially extending surface as indicated at 83 in Fig. 3. When the shell 25 is turned counterclockwise, the abrupt surface 83 firmly engages and pushes on the abrupt surface 79 to move the housing 16 counterclockwise with the shellO Thus, there is a firm driving connection between the shell 25 and the .; .
housing 16 in the direction which disengages the thread 19 from the thread 12, i.e., the direction which moves the seal 22 axially . . .
~! away from the lip 13.

The camming surface 82 of each pocket 26 i8 proportioned and designed such that, when the shell 25 and housing 16 are being turned ` in a clockwise direction and there is a predetermined torque resis-!` tance to rotation of the housing 16, the lug 24 will be cammed axially inwardly to permit the shell 25 to move clockwise relative to the housing 16. Since there are four equally peripherally spaced pockets 26 and two equally peripherally spaced lugs 24, when the lugs 24 are cammed inwardly, the shell will move 90 relative to the housing 16 before the lugs will engage another set of pockets 26.
The said predetermined torque resistance at which the lugs 24 will be cammed inwardly is set at a level which will prevent over-compression of the sealing ring 22. The predetermined torque resis-tance will, of course, be sufficient to provide a proper seal be-tween the housing 16 and the lip 13.

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10~70644 , In the illustrative and preferred embodiment, the housing 16 is integrally formed by a molding proce~s to provide the shank 18, flange 17, finger~ 23a and lugs 24 a~ well as the valve passageway extending axially through the housing 16. Ac~
ceptable materials from which the hou~ing 16 may be molded are Acetal DELRIN 100 or CELCON M-2504, DELRIN and CELCON both being trade mark~ for polyoxymethylenes, with CELCON being a copolymer and DELRIN being the homopolymer. ~he shell 25, of course, may be formed from ~heet metal using conventional sheet metal cap forming techniques.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A cap for closing a chamber having a filler neck which is provided with an internal thread and with a peripherally extending lip at its mouth, said cap comprising a housing having a longitudinal axis and axially spaced outer and inner end portions said housing having, at said outer end portion thereof, a radially outwardly and peripherally extending flange and, extending axially inwardly from said flange, a shank with an external thread on the outer periphery thereof, for mating with the internal thread, said flange providing at least one finger which is resiliently movable in the direction of said longitu-dinal axis, the or each finger having an axially outwardly extending lug at its distal end, a concentric sealing ring disposed adjacent said flange for sealing engagement with such a lip a shell covering at least said outer end portion of said housing, said shell providing at least one axially inwardly opening pocket, with the or each lug being adapted to be received in the pocket or a respective one of the pockets, respectively, the or each pocket being formed with a camming surface at its trailing end relative to one sense of turning of the shell relative to the housing to provide a torque limited driving connection between the shell and the housing in said one sense of turning of the shell for advancing the shank into engagement with such a filler neck, and the or each pocket having an abrupt surface at its leading end, relative to said one sense of turning of the shell, with the or each camming surface being effective to cam the lug or the respective one of the lugs, respectively, out of the pocket or the respective one of the pockets, respectively, when the limit of the torque limited driving connection between said shell and said housing is exceeded as the resistance to turning of said housing in said one sense exceeds a predetermined level.

2. A cap according to claim 1 in which the or each finger extends peripherally about a radially outer portion of said flange.

3. A cap according to claim 1 in which said shell provides a plurality of said pockets equally peripherally spaced about said axis, whereby, when the or each lug is cammed out of the respective one of said pockets, said shell rotates in said one sense relative to said housing until the or each lug engages the next adjacent pocket.

4. A cap according to claim 3 in which there are four of said pockets spaced 90° apart and two of said fingers diammetri-cally opposed with said lugs spaced 180° apart.

5. A cap according to claim 2 in which the or each pocket is disposed at the radially outer peripheral edge portion of said shell.

6. A cap according to claim 5 in which said shell includes means engaging the axially inner side of said flange to connect said shell to said housing for said relative rotation.

7. A cap according to claim 6 in which the axially inner side of the or each finger inclines axially outwardly from its proximal end to its distal end, the combined axial thickness of the or each lug and the distal end of its associated finger being not substantially greater than the axial thickness of said flange such that the or each lug and distal end can be cammed axially inwardly from the pocket or the respective one of the pockets, respectively, to move relative to said shell and said means engaging the axially inner side of said flange.

8. A cap according to claim 2 in which said housing is integrally molded of plastic to provide said flange, shank, finger or fingers and lug at the distal end of the or each finger.

9. A cap according to claim 2 in which the or each lug is generally rectangularly shaped having axially extending leading and trailing edges.

10. A cap according to claim 2 in which the or each finger is proportioned and designed such that its associated lug normally extends axially outwardly from the outer side of said flange into engagement with the pocket or the respective one of the pockets, respectively, the distal end portion of the or each finger being movable axially inwardly so that its associated lug does not protrude axially beyond the axially outer surface of said flange.