EP1753674B1 - Aerosol can comprising an inner shell - Google Patents

Abstract

The invention relates to a pressurized can comprising a body, a valve arranged in a dome, a base (16), an inner shell (1) with detachable, push-off type cover (8) arranged on the base (16) and a movable shaft (7) arranged in a fixing element (2) and extending through the base (16) into the inner shell (1) and serving as release element for the inner shell with the inner shell (1) being connected to the base (16) via the fixing element (2), moreover comprising a piston element (3) movable in longitudinal direction of the inner shell (1) and being arranged inside the inner shell (1), the piston element yielding a sealing effect at the inner shell's (1) inner wall and interacting with the shaft (7) in such a manner that when the shaft (7) is moved into the inner shell (1) the piston element (3) causes a liquid present inside the inner shell (1) to be pressurized so that the cover (8) is forced off.

Description

The invention relates to a pressure cell with a frame, a arranged in a dome valve, a bottom, an arranged on the bottom inner sleeve with absprengbarem closure and arranged in a holding element and reaching through the bottom into the inner sleeve movable shaft, the part of the trigger mechanism for the Inner sleeve is, wherein the inner sleeve is connected via the retaining element to the ground. Such pressure can be used for example for the application of 2-component mounting foams or 2-component paints.

The invention relates to the formation of pressure cans, which in addition to the main component, which is required for the manufacture and application of polyurethane foams or paints, in the inner sleeve have a second component which reacts with the main component to the finished product, the actual foam or paint , Equally, however, the invention can also be used for 2-component formulations for other purposes, for example in surface technology and for adhesives.

The substances contained in the pressure vessels are usually liquid and consist of a prepolymer, conventional additives and the liquid propellant, which is used for discharging the contents of the pressure vessel. The further component is present in an inner sleeve in a relatively small amount and usually consists of a compound which reacts rapidly with the main component, in the case of polyurethane prepolymers with reactive isocyanate groups, for example, a crosslinker in the form of a hydroxy compound, an amine, optionally together with catalysts. The component in the inner sleeve serves to influence the curing and the quality of the product, generally accelerating the curing. The second component is introduced shortly before the dispensing of the contents of the can by breaking the lid of the inner container in the pressure cell and mixed by shaking therein. The finished mixture must then be applied within a defined time to prevent curing in the can.

Out DE-U-82 27 229 is a pressure cell with a by forming a metal-made molded part obtained one-piece soil known. In a recess of this bottom of the externally threaded neck of an additional container is inserted and braced by means of a nut screwed from the outside under deformation of an O-ring seal between a shoulder of the additional container and the inner edge of the bottom recess. The guided in turn by a piston-shaped seal into the interior of the additional container and sealed rod is designed as a shaft which rotates in the Zusatzbehälterhals and is supported inside on this. If the shaft is driven from the outside, this leads to the positive engagement of its inner end with the lid of the additional container, which is thereby blasted off against the internal pressure in the can.

The starting point of the invention is WO-A-85/00157 in which a pressure cell for discharging single- or multi-component substances is described, which has in its interior a further component receiving additional container. The inner container has an inner lid, which can be blasted off via a guided through the bottom of the pressure cell into the interior of the inner container rod. The plunger is movably mounted within the additional container and inserted through a arranged in the sickle plate of the can bottom seal. A corresponding pressure cell is in FIG. 1 shown.

Both pressure sockets according to the prior art require a relatively complex construction or assembly. The container suffers according to DE-U-82 27 229 under the relatively complicated mechanics. The breaking off of the lid against the relatively large internal pressure of the container is indeed through the However, this is relatively cumbersome and requires a lot of effort for the sealing system.

The pressure cell according to WO-A-85/00157 Although it has been proven successful and represents a significant improvement over the said utility model, but the introduction of the plunger is problematic due to the strained in the sickle plate rubber seal and requires a non-optimal geometry of the plunger.

Both pressure cell according to the prior art also have systemic sealing problems, which is based on the - after filling with propellant gas - automatically building pressure difference between outer prepolymer and existing in the inner sleeve hardener component. During the storage life of the can, which may well be several months, this pressure difference is essentially due to the fact that the outer prepolymer penetrates into the inner sleeve. Although slow, this process involves only small amounts, so that the actual chemical reaction that leads to the curing is not affected. However, a problem is the reaction product, which deposits in the area of the seals and in particular in the area of the lid and leads to adhesions. In addition, the resulting particles in the case of a 2-component paint spray for the quality of the paint coating produced therewith are disadvantageous.

The invention is therefore based on the object, the pressure cell according to WO-A-85/00157 educate so that the parts of the inner sleeve can not only easier to assemble a captive and absolutely dense unit, but also to defuse the occurring due to the pressure difference occurring leakage problem between the outer space of the pressure cell and inner sleeve.

This object is achieved with a pressure cell of the type mentioned above in that in the inner sleeve a movable piston member in the longitudinal direction of the inner sleeve is arranged, which seals against the inner wall of the inner sleeve and cooperates with the shaft in such a way that upon movement of the shaft into the inner sleeve the piston element is located in the inner sleeve liquid under pressure, so that the shutter is blown off.

Essential for the pressure cell according to the invention and in particular the operation of the inner sleeve is that the piston element is arranged to be movable inside the pressure cell. In this way, after filling the pressure cell with the propellant gas mixture, which increases the pressure in the outer space of the pressure cell significantly, a pressure equalization by a slight displacement of the piston element. The piston member moves upwardly within the inner sleeve until within the inner sleeve the pressure prevailing in the outer space of the can has been established. This eliminates the pressure difference responsible for the seepage of prepolymer into the inner sleeve.

The inner sleeve has a closure or lid on the valve side, which can be fitted in any manner there form fit. At the periphery of the lid is a sealing element, which may for example be in the form of an O-ring, which is mounted in a groove of the lid and engages in a groove on the inside of the inner sleeve. Other sealing variants are possible. However, a lip seal is preferred, which rests sealingly against the inner wall of the inner sleeve and optionally cooperates with a circumferential groove or a projection there.

At the bottom end of the inner sleeve is the piston element, which is preferably designed as well as the closure or the lid. Again, located in the periphery of the piston member is a sealing element, preferably a lip seal, which acts against the inner wall of the inner sleeve. Here are expediently groove and the like on the inner wall is not provided to allow a simple displacement of the piston member for the purpose of pressure equalization and also in the blasting of the lid.

The term "blasting" or "absprengbar" is to be understood according to the invention that it refers to the pushing out, pushing out or loosening of the closure element or lid at the valve end of the inner sleeve. Of the Term "triggering" refers to the activation of the inner sleeve by the breaking of the cap after actuation of the shaft.

The piston element preferably has on its underside a recess in a cylindrical shape into which engages the piston shaft or plunger and is supported. The stem or plunger is part of the triggering mechanism and the movable element with which during the release process force is transferred from the outside of the can to the piston element and thus to the filling located in the inner sleeve, usually a more or less viscous liquid. The hydraulic pressure then causes the break-off of the closure element or lid.

The stem is thus the central element of the triggering mechanism, but not the only element. What is essential is the more or less complete transfer of the pressure exerted by the shaft on the fluid in the inner sleeve. The invention is based on the recognition that it is readily possible to dispense with a ram reaching to the cap when the pressure on the sleeve liquid can be transferred to the cap. In fact, some of the problems of pressure cans known in the art are due to the relatively rigid plunger-to-closure cap arrangement. The piston solution used according to the invention allows a pressure equalization in that the piston element shifts slightly into the inner sleeve under the pressure of the prepolymer component in the outer container. The pressure is transferred according to the invention solely by the liquid column in the inner sleeve from the piston member to the cap.

The inner sleeve itself is mounted on a holding element which projects through the bottom of the can and accommodates the shaft or plunger in it. The retaining element serves primarily as a guide for the shaft. It may, for example, be sprayed on a sickle plate, wherein the sickle plate is part of the can bottom and is crimped with a vaulted bottom element. The floor element itself is crimped with the frame of the box.

Alternatively, the holding member may also be passed through a central opening in the bottom floor, which is useful especially when drawn aluminum cans. In this case, it is expedient to provide a seal, for example a rubber sealing disc, between an outer circumferential projection of the retaining element and the inner side of the base of the can. Retaining elements with seal are clamped by a suitable securing element on the outside of the can bottom against the bottom of the can. Such a securing element is for example a conventional spring washer.

Inner sleeve and retaining element are connected to each other, for example via suitable locking elements. It may be useful to design this compound sealing, but this is usually not necessary; to simplify the pressure balance between the contents of the can and the contents of the inner sleeve, it is expedient to allow the contents of the can to enter freely into the lower space of the inner sleeve up to the piston element. For this purpose, openings may be provided in the sleeve wall in the bottom region below the piston.

It is expedient to provide limiting elements on the shaft or plunger, in particular an inner limiting element which limits the downward movement of the shaft towards the bottom of the can. This limiting element can also be designed as a sealing element which acts sealingly against the inner wall of the holding element. An approximately in height of the bottom element circumferential projection serves as an abutment for the limiting element and thus limits its downward movement. At the same time this projection causes an additional sealing effect, especially when the limiting element is designed to be elastic.

Outside the pressure cell, the shaft may have a further limiting element which limits the upward movement of the shaft when the inner sleeve is triggered. Conveniently, this limitation is via a protruding collar, which can be braced against the circumferential projection at the level of the bottom element. For mounting, it makes sense to interpret this outer limiting element so that it is in the assembly from above, So from the valve side, can be pushed or plugged through the holding element with its inner circumferential projection.

For cost reasons, it may be expedient to design the closure or lid and piston element of identical design. In this case, both closure and piston element have the same seal, preferably lip seal. A lip seal, which acts both upwards and downwards against the inner wall, also has the advantage that the piston / cover is properly guided on the wall.

The holding element is inventively designed as a tube-like structure through which the shaft extends from the piston element through the bottom of the can through to the outside of the can. An outer peripheral projection serves to secure the retaining element on the bottom of the can, either by injection molding on the inner edge of the bottom element, or by bracing with the bottom element. An inner circumferential projection in height of about the can bottom serves as an abutment for limiting elements that may be provided on the shaft.

The bottom end of the shaft, which projects outwardly through the bottom of the can, expediently engages in a sleeve which can be actuated to trigger the snap-off mechanism. An upward movement of the sleeve causes the shaft with the piston element located above it to move upwards and the closure is pushed out or blasted out by the hydraulic pressure triggered thereby. The sleeve may be formed for example as a push button, which is suitably guided with a cylindrical guide on the outer wall of the outer part of the support member, but for example, be slidably mounted within a recess of a cap arranged on the bottom of the can.

According to a variant, the retaining element has on its bottom-side part concentrically around the shaft an internal thread into which engages a sleeve with an external thread. The bottom end of the shaft extends into a central bore of the screw. Screwing the sleeve into the retaining element thus causes the upward movement of the shaft and piston element and thus the triggering of the inner sleeve.

To facilitate the rotational movement, a cap can also be provided here, which cooperates in a central recess or a central shaft with the sleeve force and form-fitting manner. In this case, the cap is expediently provided with a guide and locked in a located on the outside of the outer part of the retaining element circumferential groove. The cap is designed as a rotary cap, so that upon rotation, the sleeve is screwed with its external thread in the retaining element.

Figur 1

eine Druckdose mit Innenhülse gemäß Stand der Technik ( WO-A-85/00157 );

Figur 2

den unteren Teil einer erfindungsgemäßen Druckdose mit eingewölbten Boden und aufgesetzter Kappe im Schnitt;

Figur 3

die Ausführungsform von Fig. 2 als Schnittzeichnung;

Figur 4

eine weitere Variante der Ausführungsform von Fig. 3; und

Figur 5

eine Innenhülse gemäß Fig. 2, die einen umspritzten Sickenteller und einen Druckknopf zur Auslösung aufweist.

The invention is explained in more detail by the accompanying drawings. Show it:

FIG. 1

a pressure cell with inner sleeve according to the prior art ( WO-A-85/00157 );

FIG. 2

the lower part of a pressure cell according to the invention with vaulted bottom and attached cap in section;

FIG. 3

the embodiment of Fig. 2 as a sectional drawing;

FIG. 4

a further variant of the embodiment of Fig. 3 ; and

FIG. 5

an inner sleeve according to Fig. 2 , which has an over-molded sickle plate and a push button to trigger.

The pressure box I according to FIG. 1 consists of a frame II, which is closed at the top with a Dom III. The Dom III has a flanged edge, which connects the Dom III with the frame II and at the same time brings about a tight connection of the parts. The Dom III is made of a round plate, a molded part made of sheet metal, which has been given the arched form shown in the drawing by forming. The inner edge of the Dom III is again crimped and receives a valve plate with a valve IV.

The bottom 16 is also connected via a flanged edge with the frame II and has a sickle plate 15 in its center, above which the inner sleeve 1 is located. The inner sleeve 1 has a blow-off cover 8. Inside the inner sleeve 1 is a plunger 7, the end of which is led out through a sealing element 18 below from the pressure cell and extends up to the cover 8. On both sides of the sealing element 18, the plunger has limiting elements, an upper or an inner 4 and a lower or outer 5, both of which act against the sealing element 18 and limit the free path length of the plunger 7 within the inner container 1. To break off the lid 8 from the inner container 1, the plunger 7 is pressed by striking the can bottom on a solid surface and placed in an upward movement. The rubber-elastic sealing element 18 catches this upward movement and, after breaking off the cover 8, returns the plunger 7 to its starting position. A cap 29 protects the plunger end.

FIG. 2 shows a sectional view of the lower part of a pressure box according to the invention. The preferred embodiment according to Fig. 2 shows the bottom portion of the can body II with the vaulted bottom element 16: It is a drawn (aluminum) pressure cell. Inside the pressure cell is the inner sleeve 1, the interior 9 is limited by the cap 8 and the piston member 3. The inner sleeve 1 is fixed to the retaining element 2 by means of a latching connection. The holding element itself extends through the bottom 16 of the pressure box to the outside and is clamped with this over a circumferential projection, a sealing washer and a spring washer. The shaft 7 has an upper and a lower boundary, which act against a in the holding element 2 inside circumferential projection. Upon actuation of the shaft 7 by pressing with the knob arranged outside the pressure cell, the piston 3 moves in the direction of the closure cap 8, puts the liquid in the space 9 under pressure, so that the hydraulic pressure pushes the cap 8 from the inner sleeve 1 or pops out.

In the bottom region of the pressure cell is a cap which is locked with a cylindrical guide element at the end projecting through the bottom of the retaining element 2 and is supported against the pressure cell in the outer region of the concavity. The depression in the floor area allows for a fixation on the holding element and serves as a vertical guide for the push button.

FIG. 3 is a sectional view of the lower part of the representation of Fig. 2 ,

According to Fig. 3 The piston element 3 has on its periphery a lip seal 13 which acts against the inner wall of the inner sleeve 1. The nature of the seal, which has an upper and a lower lip, also causes a certain guide on the wall, which facilitates the displacement of the piston.

The piston element has centrally a cavity 10 into which the shaft 7 engages with its sleeve-side end 7b. The bottom end of the shaft 7 engages with the head 7a in a corresponding receptacle 11 on the sleeve / the push button 6 a.

The shaft 7 has in its central region on two limiting elements 4 and 5, of which the inner 4 is simultaneously designed as an elastic seal which acts against the inner wall of the retaining element 2. The bottom-side limiting element is designed as an elastic collar which is open on the valve side. Both limiting elements cooperate with a circumferential inside the holding element projection 17, which represents a Auffangstellung during the upward or downward movement of the shaft 7, in particular in the release of the inner sleeve. At the same time the circumferential projection 17 serves as a sealing seat for the element 4 in its function as a sealing element. The distance of the limiting elements 4 and 5 coincides with the maximum available for the triggering path length of the shaft 7.

The holding element 2 is a plastic molded part, which has a continuous bore for receiving the shaft 7. An outer circumferential projection 12, which is lined with a sealing washer 18, serves to fix the bottom element 16 in the region of its central recess. The retaining element is at the bottom by means of a securing element, here a spring washer 19, secured.

The inner sleeve 1 is locked at 14 via integrally formed webs 1a by means of a locking element in a circumferential groove of the retaining element 2. Since the seal of the pressure cell outwardly through the projection 17 and the element 4 and the inner sleeve out through the lip seal 13 on the piston element 3, located below the piston member 3 cavity of the inner sleeve 1 for the content of the outer box space can be freely accessible. This facilitates the pressure balance between the outer space and the sleeve space 9, in particular when exposed to propellant gas.

The holding element 2 shows in the lower region of the opening an internal thread, which may be of importance for other embodiments, see Fig. 4 ,

In the area of the bottom of the can there is a cap 29, which has a central recess 30, which in turn has a shoulder on a cylindrical shape 31 which is latched via a protruding there inside projection with the lower end of the support member 2 in a groove , The recess 30 has vertically extending walls, which also serve as a guide for the push button 6, with which the shaft 7 is pressed upon activation of the inner sleeve into the can interior.

FIG. 4 shows a variant of the embodiment of Fig. 3 in which the threaded structure 20 shown at the bottom end of the retaining element 2 cooperates with a threaded sleeve 6 with an external thread 21. The screw sleeve 6 has a bore 22 in which the bottom end of the shaft 7 is mounted and abuts with its end portion 7a to the bottom 23 of the threaded sleeve 6.

The screw 6 itself is fitted in a receptacle 30 such that a positive connection is formed, for example via a hexagonal structure. The cap 29 is latched with a hollow cylindrical projection 31 below the bottom element 16 with the retaining element 2. The locking takes place in such a way that the Cap 29 can rotate with the sleeve 6, so that the sleeve 6 screwed into the existing at the bottom end of the retaining element 2 internal thread and thereby drives the shaft 7 with the piston member 3 in the inner sleeve. The rotational movement of the cap 29 thus leads to the triggering of the inner sleeve. 1

FIG. 5 shows a variant of a pressure cell according to the invention, in which the bottom of the can 16 has an additional sickle plate 17. Such sickle plates are used in particular for pressure cans, which are made of tinplate. The sickle plate itself is crimped on its outside with the bottom 16 in position 25. In the region of the inner opening, the holding element 2 is molded so that the partially flanged inner edge 24 of the sickle plate 17 is completely embedded in the plastic compound of the holding element 2.

As in the embodiment according to Fig. 3 the bottom end of the shaft 7 is received in a receptacle 11 of a sleeve or a push button 6, which sets by pressing in the direction of the bottom of the can the trigger mechanism in motion. In this case, the push button 6 is guided with an internally molded hollow cylinder on the outer wall of the holding element 2 and with its outer walls of the Krimpnaht 25 which connects the sickle plate 17 with the bottom element 16.

Claims (17)

1. Pressurized can comprising a body, a valve arranged in a dome, a base (16), an inner shell (1) with detachable, push-off type cover (8) arranged on the base (16) and a movable shaft (7) arranged in a fixing element (2) and extending through the base (16) into the inner shell (1) and serving as release element for the inner shell with said inner shell (1) being connected to the base (16) via the fixing element (2)
   characterized in that a piston element (3) movable in longitudinal direction of the inner shell (1) is arranged inside the inner shell (1), said element yielding a sealing effect at the inner shell's (1) inner wall and interacting with the shaft (7) in such a manner that when the shaft (7) is moved into the inner shell (1) the piston element (3) causes a liquid present inside the inner shell (1) to be pressurized so that the cover (8) is forced off.
2. Pressurized can according to claim 1, characterized in that the fixing element (2) is arranged, preferably by molding, on a beaded cup (15) located and crimped onto base (16).
3. Pressurized can according to claim 1, characterized in that the fixing element (2) is secured via a securing element (19) in an opening of base (16) with a sealing element (18) being arranged between base (16) and a circumferential outer projection (12) of fixing element (2).
4. Pressurized can according to claim 3, characterized in that the securing element (19) is a spring washer.
5. Pressurized can according to any one of claims 1 to 4, characterized in that shaft (7) has an inner limiting element (4) which interacts with a circumferential inner projection (17) of fixing element (2).
6. Pressurized can according to claim 5, characterized in that the shaft (7) has also been provided with an outer limiting element (5).
7. Pressurized can according to any one of the claims 1 to 6, characterized in that the inner shell (1) engages with fixing element (2).
8. Pressurized can according to any of the above claims, characterized in that the piston element (3) and the closure cover (8) are of identical design.
9. Pressurized can according to any of the above claims, characterized in that the piston element and/or the closure cover (8) are provided with lip seals (13) acting against the inner wall of the inner shell (1).
10. Pressurized can according to any one of the above claims, characterized in that the piston element (3) has a central recess (10) in which the can-side end (7b) of shaft (7) is secured.
11. Pressurized can according to any one of claims 1 to 10, characterized in that the outer end (7a) of the shaft (7) engages with a sleeve (6) which can be actuated with a view to tripping the release mechanism.
12. Pressurized can according to claim 11, characterized in that the sleeve (6) has an inner guide (30) concentrically encompassing that part of fixing element (2) located outside the pressurized can.
13. Pressurized can according to claim 11, characterized in that the fixing element (2) is provided with a female thread (20) on its portion located outside the pressurized can, said female thread encompassing shaft (7) concentrically.
14. Pressurized can according to claim 13, characterized in that sleeve (6) has a male thread (21) interacting with female thread (20) thus driving shaft (7) into the inner shell (1) when the sleeve (6) is rotated and thus moved into the fixing element (2).
15. Pressurized can according to any one of claims 1 to 14, characterized in that the can has been provided with a cap (29) secured at the pressurized can or fixing element (2) and being provided with a central recess and opening accommodating the release mechanism.
16. Pressurized can according to claim 15 in conjunction with claim 14, characterized in that the cap (29) is designed so as to be rotatable with said cap in the area of the central recess being connected with sleeve (6) in a form- and force-closed manner.
17. Use of a pressurized can according to any one of the above claims for the discharge of two-component mounting foams or two-component paint materials.

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