DK179185B1 - Piston arrangement for repair of laminated glass - Google Patents

Abstract

A piston arrangement (1) is disclosed for use in repairing damage (17) to laminated glass (18), preferably a car window, by resin injection. The piston arrangement (1) comprises a first piston body (32) disposed displaceably in a bore (36) in an injection tube (4) and having a piston surface (2) defining a resin chamber (5). The piston arrangement (1) further comprises another piston body (7) which is slidably disposed in a sheath (22) and which forms an internal pressure chamber (6). In the first piston body (32), an opening (8) is formed which establishes a connection between the resin chamber (5) and the internal pressure chamber (6). To prevent resin from entering the opening (8) and causing a risk of clogging, sealing means (34) are provided on the first piston body (32) which seals against an inner wall of the bore (36) and the opening (8) is formed in it. the side wall of the first piston body (32) in a position between the sealing means (34) and the piston surface (2).

Description

ϋθ> DENMARK (10)

< ¹² > PATENT WRITING

Patent and

Trademark Office (51) Int.CI: B 32 B 17/10 (2006.01) (21) Application number: PA 2016 70083 (22) Filing date: 2016-02-15 (24) Running day: 2016-02-15 (41) Aim . available: 2017-11-07 (45) Patent Notice bkg. on: 2018-01-15 (73) Patent holder: Greentek I Racing v / Claus Grøndal, Nørhedevej 46, 8600 Silkeborg, Denmark (72) Inventor: Claus Grøndal, Nørhedevej 46, 8600 Silkeborg, Denmark (74) Proxy: Patrade A / S, Fredens Torv 3A, 8000 Aarhus C, Denmark (54) Name: Stamp arrangement for repair of laminated glass (56) Publications published:

WO 2010/130264 A1 US 3993520 A1 US 2002/0058080 A1 GB 2308622 A (57) Summary:

A piston arrangement (1) is disclosed for use in repairing damage (17) to laminated glass (18), preferably a car window, by resin injection. The piston arrangement (1) comprises a first piston body (32) disposed displaceably in a bore (36) in an injection tube (4) and having a piston surface (2) defining a resin chamber (5). The piston arrangement (1) further comprises another piston body (7) which is slidably disposed in a sheath (22) and which forms an internal pressure chamber (6). In the first piston body (32), an opening (8) is formed which establishes a connection between the resin chamber (5) and the internal pressure chamber (6). To prevent resin from entering the opening (8) and causing a risk of clogging, sealing means (34) are arranged on the first piston body (32) which seals against an inner wall of the bore (36) and the opening (8) is formed in it. the side wall of the first piston body (32) in a position between the sealing means (34) and the piston surface (2).

To be continued ...

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Piston arrangement for repair of laminated glass

FIELD OF THE INVENTION

The present invention relates to a piston arrangement for use in repairing damage to laminated glass, preferably a car window, by injection of resin, the piston arrangement comprising a first piston body slidably disposed in a bore of an injection tube and having a first piston crown with a piston surface adapted for tightly fitting into a gasket member in the injection tube, which gasket encloses a resin chamber, further comprising a second piston body slidably disposed in a sheath and having a second piston crown sealingly abutting against the inside of the sheath. and forming an internal pressure chamber which has varying volume depending on the position of the second piston body in the casing and in which an opening is formed in the first piston body which establishes a connection between the resin chamber and the internal pressure chamber.

BACKGROUND OF THE INVENTION

US 3,993,520 discloses a method and tool for repairing laminated glass, particularly car windows, where a resin is injected into a crack in the glass. The tool includes a bridge that is mounted on the glass next to the damage. The bridge is held with suction cups on the glass. An injection tube is screwed into the bridge. The injection tube has means for establishing tight contact between the inner tube and the damage. Resin is filled into the lower part of the injection tube, which is referred to as a resin chamber, after which a plunger is screwed in. This creates an overpressure in the resin chamber so that the resin flows into and fills the crack. When the plunger is unscrewed, a negative pressure is created which pulls air bubbles out of the resin. The piston is alternately screwed back and forth to "massage" the resin into the crack and remove encapsulated air. This massager is repeated until the crack is filled with resin and the resin is degassed to a level where further repetitions do not result in visible changes. This is especially time-consuming for large injuries, where relatively large amounts of resin are used. Typically, an average repair takes 15-20 minutes.

If the damage is not detected immediately after it has occurred, moisture and foreign matter will penetrate the damage.

The resin has the same refractive index as the glass when cured, so that the repaired damage is virtually undetectable, provided that it is possible to extract all visible air bubbles, trapped foreign matter and moisture in the resin. If this is not the case, the repaired damage will remain visible to a greater or lesser extent. Therefore, the size of the negative pressure needed to repair an injury so that it becomes invisible depends on the size of the damage, as this determines the amount of resin to be degassed, the age of the damage, which determines the amount of moisture and foreign matter. that has penetrated the damage and whether the damage has been off the tire.

The area of the piston and its migration defines the size of the overpressure and negative pressure that can be achieved. As an incompressible fluid is pressed, very high overpressures (> 100 psi ~ 6.8 atm.) Can be achieved. Therefore, it is desirable to have a relatively small piston area and a hike, which provides better opportunities for fine-tuning the pressure to prevent the pressure from getting too high during the resin pressure, so that the glass around the damage will break.

When the plunger is unscrewed, a compressible gas is drawn. Therefore, the maximum size of the negative pressure obtainable with the same size of the piston is limited and not close to the absolute and maximum negative pressure (latm). The rate at which the resin is degassed, as well as the size of the foreign matter that can be extracted from the injury, are directly dependent on the size of the vacuum.

Thus, it is desirable to obtain an overpressure of a limited size under the pressure of resin, so that the crack does not deteriorate, while it is desirable during the formation of suppression that this becomes as large as possible for faster gasification of the resin and for repair cracks containing foreign matter and moisture due to insufficient coverage or large cracks.

The use of the repair tool according to US 3,993,520 therefore assumes that there is minor damage and that the damage is repaired or uncovered immediately after the damage occurred, so that moisture and other foreign matter do not penetrate the crack because the size of the piston is limited of the permissible maximum overpressure by pressing the resin which then causes a significant reduction in the size of the obtainable underpressure. This results in a repair where there may be foreign matter contained or moisture in the damage, which remains visible despite the repair.

In order to remedy the disadvantages of these known tools, a tool of the type mentioned in the introduction is described in WO 2010/130264. This tool has been found to be very suitable for repairing even large cracks, and cracks containing moisture and foreign matter, the repairer being able to add a negative pressure greater than that of the piston surface alone. This makes it possible to extract even large amounts of moisture and large foreign matter due to the greater negative pressure. In addition, the effect is obtained that the degassing of the resin proceeds rapidly and becomes more elaborate.

However, it has been found that in use there is a risk that the workwear will become clogged due to insufficient care when cleaning after the repairer has completed his repair. The opening establishing the connection between the resin chamber and the internal pressure chamber is located in the piston surface. In the absence of cleaning, it has therefore been found that hardened resin will stop the opening and thus the first piston body must be replaced in order for the tool to remain usable.

The object of the invention

It is an object of the invention to provide a tool for repairing damage in laminated glass panes and where the tool is not associated with the disadvantage of the known tools and is easy to clean. The design of the tool makes it suitable for repairing both small and large cracks and especially cracks containing moisture and foreign matter. It is also an object of the invention that the tool can be used in existing glass pane repair systems.

Description of the Invention

This is achieved in accordance with the present invention with a piston arrangement of the type mentioned initially, characterized in that sealing means are arranged on the first piston body which seals against an inner wall of the bore and that the opening is formed in the side wall of the first piston body in a position between the sealing means and the piston surface.

Since the opening is formed in the side wall of the first piston body at a distance above the piston surface, there is very little risk of resin coming into contact with the opening. The resin chamber is bounded by the piston surface and the enclosing packing means and therefore there is no risk of resin penetrating along the side wall of the first piston body and penetrating the opening.

Should resin be drawn into the opening, the piston arrangement can be easily cleaned by compressed air blowing.

With the piston arrangement, it is possible with the second piston body to establish a second negative pressure in the resin chamber, for extracting moisture and foreign matter from the damage, which negative pressure is greater than a maximum size of a first negative pressure which can be established by means of the first piston body.

Hereby it is possible to repair even large cracks, and cracks containing moisture and foreign matter, as the repairer has the opportunity to add a negative pressure greater than that which the piston surface alone can perform. This makes it possible to extract even large amounts of moisture and large foreign matter due to the greater negative pressure. In addition, the effect is obtained that the degassing of the resin proceeds rapidly and becomes more elaborate.

The size of the total negative pressure that can be formed in the resin chamber during the process is the first negative pressure added with the second negative pressure.

Furthermore, it is achieved that the piston surface of the piston arrangement with the first piston body in its first outer position can function as a conventional piston, where an overpressure can be established in the resin chamber so that the resin is pressed in and fills the damage in the glass. This overpressure has a limited size, so it avoids aggravating the damage.

In addition, a first negative pressure can be established in the resin chamber for degassing the resin. This negative pressure is of limited size and will in some cases be sufficient to degass the resin sufficiently, but in many cases only contribute to a partial degassing of the resin and not at all sufficient to extract moisture and foreign matter.

In the latter cases, the first piston body is displaced toward its second outer position, thereby establishing connection between the internal pressure chamber and the resin chamber through the opening and a second negative pressure is established. The overall negative pressure in the resin increases beyond what the piston surface alone can affect it. This is suppressed by a size where moisture and foreign matter can be extracted from the damage and where the degassing of the resin proceeds quickly and without the need for a time-consuming massager back and forth with the piston surface.

The skilled person repairing damage in laminated glass will, with the piston arrangement, be able to repair both small and large damage, with and without moisture and foreign matter, in a quick and simple manner, and with a quality of repair where it appears invisible.

During the practice, a support tool is used - a so-called "bridge", which is temporarily attached to the glass over the damage by means of suction cups which can be released when the repair is completed. The support tool typically has a through threaded hole adapted to receive the injection tube which has a cooperating thread on the outside so that it can be screwed into the threaded hole.

The injection tube packing member is typically configured to be sealed against the glass surface when the injection tube is screwed into the support tool and is in close contact with the first piston body when inserted into the injection tube to form a pressure-tight resin chamber in front of the piston chamber. and above the glass surface.

The packing means may advantageously be provided with one or more lip seals along the inside. These lip gaskets are directional so that they either close tightly around the portion of the piston arrangement inserted into the gasket by suppression or overpressure in the resin chamber, depending on their location along the length of the gasket.

Typically, the biasing force of the injection tube against the glass surface can be read by assessing how much the packing means is expanded. This is done by inspecting the gasket from the opposite side to the glass. This inspection can be facilitated by placing a mirror, typically held with suction cups on the inside of the glass, next to the damage so that the repairer can perform this inspection from the outside.

The piston arrangement of the invention is particularly suitable for use with a support tool and an injection tube with a gasket member known from US 3,993,520.

When the support tool and the injection tube with gasket means are positioned as desired, resin is filled into the injection chamber. This can be done with a syringe having a needle long enough to reach the injection tube and the resin chamber gasket.

The piston arrangement having a diameter corresponding to the inner diameter of the packing means is inserted into the injection tube. This creates an overpressure in front of the piston surface, which forces the resin to flow from the resin chamber and into the damage. In this way the damage is filled with resin.

The piston surface is then returned so that a first negative pressure is created in front of the piston surface. Since the resin has a higher viscosity, most of the resin will remain in the damage, while the trapped air bubbles in the resin will be pulled out.

Another negative pressure can be established in the resin by means of an internal pressure chamber for extraction of foreign matter and moisture, as well as faster degassing. The second negative pressure is obtained by displacing the second piston body in the internal pressure chamber. The volume of the pressure chamber is determined by the location of the second piston body. In the second piston DK 179185 B1 seen, the first outer position is stored, the volume of the pressure chamber is at least and in the second outer position of the second piston body the volume of the pressure chamber is greatest.

Typically, the piston arrangement is formed with a cylindrical cavity in which the second piston body is arranged with a gasket member. The sealing means is arranged to close tightly to the inside of the cylindrical cavity during longitudinal displacement of the piston body, to establish a pressure chamber.

In an alternative embodiment, the plunger arrangement is formed with a sheath into which a commercially available disposable syringe is inserted. The plunger body is provided with the gasket member from the syringe and provided with a tip extending down into the interior of the plunger assembly.

Hereby formation of the piston arrangement is achieved in a particularly simple manner, where a secure density is obtained, the interior of the syringe and the packing means having a demonstrated density. Thus, one is less sensitive to production tolerances.

The repairer continues to repeat the individual steps of the repair cycle until no improvements are achieved by further repetitions.

During the use of the tool there are holding times for the different process steps. With a piston arrangement according to the invention, an average repair of an injury typically takes 8-10 minutes.

With a piston arrangement according to the invention, only a limited number of repetitions are necessary in relation to the prior art. As these types of repairs are often performed on a chord, it is very important that repairs can be performed in the shortest possible time, but with the best possible quality.

Since the invention can be applied directly with already known and widespread repair systems, the repairer can avoid bringing several different types of repair systems. This also means that the individual repairer should receive instruction only in using the new piston arrangement together with the known injection tube and support arrangement, and only the part of the method relating to the second vacuum. If for any reason the repairer wishes to be able to freely switch between a system of the type known as US 3,993,520 and the system of the present application, this can easily be done since the system can be used without permanently changing the known elements.

With a piston arrangement according to the invention less resin is used than in known systems. Thus, with the new tool, only 0.15 ml of resin is used as opposed to known tools where 0.20 ml is used. Thus, the plunger arrangement of the invention enables a saving of consumable material in a repair.

For the production of a piston arrangement according to the invention, a combination of plastic and aluminum can be used. Other metals can be used instead of aluminum.

According to a further embodiment, the piston arrangement according to the invention is characterized in that the connection between the resin chamber and the internal pressure chamber is closed when the piston body is in a first outer position where it is pressed in the bottom of the injection tube and that the connection is established when the first piston body is displaced from a first outer position at such a distance that the piston surface is brought out of the tightly sealed insertion into the packing means.

With this embodiment, it is possible that the first overpressure is provided by the first piston body, whereby resin can be pressed into an injury. When the first piston body is displaced so that the piston surface is removed from the tightly sealing engagement, a connection is established so that the second piston body can be used to establish a vacuum for extracting moisture and air from the damage.

According to a further embodiment, the piston arrangement according to the invention is characterized in that the piston arrangement has an external thread which is complementary to an internal thread in the injection tube.

By using a threaded joint a particularly simple construction is obtained. Since the piston arrangement of the invention has a thread which corresponds to the inner thread of the injection tube, the above-mentioned advantage of using the piston arrangement is achieved with a system of the type known from US 3,993,520.

According to a further embodiment, the piston arrangement according to the invention is characterized in that the first piston body has a reduced diameter in a region between the opening and the piston surface.

In this embodiment, an annular connecting channel between the first piston body and the injection tube will simply be established. This will ensure the possibility of the connection between the pressure chamber and the resin chamber.

According to a further embodiment, the piston arrangement according to the invention is characterized in that the sealing means comprise at least one and preferably two O-rings.

An O-ring is a particularly suitable sealing member. However, other packing types may also be used.

According to a further embodiment, the piston arrangement according to the invention is characterized in that a visual indication is provided on the first piston body showing that the piston surface is brought out of the tightly fitting insertion in the packing means.

By the visual indication, the operator will readily know that the tight-fitting engagement between the piston surface and the packing means is complete, and that it is thereby possible to use the second piston for establishing negative pressure.

According to a further embodiment, the piston arrangement according to the invention is characterized in that the outer threads of the piston arrangement are provided on the first piston body.

This ensures that the overall piston arrangement can be screwed into the injection tube in a known system.

According to a further embodiment, the piston arrangement according to the invention is characterized in that the visual indication is a colored ring on the outer threads of the first piston body and that it is placed so that it is visible outside the injection tube when the piston surface is brought out of the tightly fitting insertion into the packing means.

The visual indication can be easily established by providing an annular area with a color mark. When applied to the outer thread of the first piston body, it can be ensured that the thread is still engaged with the inner thread of the injection tube. Thus, the various parts of the piston arrangement will not be disengaged.

According to a further embodiment, the piston arrangement according to the invention is characterized in that the piston arrangement sheath and the first piston body are releasably connected.

With this construction, it will be possible to use a separate tool, for example a disposable syringe for establishing the second piston body. The disposable syringe can easily be replaced in case of wear.

As the first piston body will typically be of metal, the first piston body will not be subject to wear in the same way as the second piston body, if this is a disposable syringe. This results in an affordable product and at the same time a product where the tightness between the valve body and sheath can be safely established.

Character description

The invention will now be explained in more detail with reference to the accompanying drawing, in which fig. 1 is a sectional view through a tool known from US 3,993,520; FIG. 2 shows a sectional view of the support tool, the injection tube and the piston arrangement known from WO 2010/130264; FIG. 3 is a view of an embodiment of a piston arrangement according to the invention and shown with the parts of the piston arrangement in a non-assembled state, π

FIG. 4 is a view of the embodiment of FIG. 3 illustrates the piston arrangement with the parts assembled and ready for use.

Fig. 5 is a sectional view through the one of Figs. 3 and 4 illustrate the piston arrangement according to the invention; 6 is a side view of the embodiment of FIG. 5, and FIG. 7 is an enlarged detail view of the embodiment of FIG. 5.

Detailed description of the invention

In the description of the figures, identical or similar elements will be denoted by the same reference numerals in the various figures. Thus, no explanation of every detail will be given in connection with each figure / embodiment.

Figure 1 shows three figures from US 3,993,520 as known in the art. The number designations used in the description below refer to FIG. 1. Only a description of the parts relevant to this application is included.

The support 20 arrangement is temporarily attached to the surface of the laminated glass 12, 13, 14 with suction cups 22. An injection tube 28 with a gasket 33 is screwed into a thread in the support arrangement 20 such that the gasket 33 is in close contact 33A with the glass surface. , over damage 11A and 1B.

Resin is loaded into the resin chamber of the injection tube (44).

A plunger 40 is inserted into the injection tube 28 with a lower portion 42 in tightly sealed contact with the seal member 33 having lip seals 33B, 33C, 33D. The lower part 42 has a piston surface, which can be applied to an over or under pressure in the resin chamber 44 depending on whether the piston 40 is screwed in or out.

As can be seen from the drawing, only a limited negative pressure can be obtained with the piston 40, the negative pressure being established with the same piston surface which creates the positive pressure, cf. the section '' Background of the invention 'in the present application.

FIG. 2 shows a laminated glass 18 with a damage 17. A support 19 tool is temporarily attached to the glass 18 with suction cups (not shown).

An injection tube 4 is located in the support tool 19 and secured with a cooperating thread. The injection tube 4 has a gasket member 3 which is tightly connected to the glass 18. The gasket member 3 has at one end a resin chamber 5 for receiving resin prior to injection into the injury 17.

A piston arrangement 1 is inserted into the injection tube 4. The piston arrangement 1 has at its lower end a piston surface 2. This piston surface 2 is in close contact with the packing means 3. It is thus possible to establish an overpressure or negative pressure in the resin chamber 5 by moving the piston surface 2 in the packing means 3.

The injection tube 4 has an inner thread 10 which cooperates with an outer thread 9 of the piston arrangement 1. Hereby the piston surface 2 can be held in a desired position in the packing means 3 and thus define a desired pressure in the resin chamber 15.

The pressure in the resin chamber 5 is increased by ice screwing of the piston arrangement and decreased by unscrewing the piston arrangement.

A packing means may be selected as shown during the review of the prior art of FIG. 1. Alternatively, a gasket member 3 may be selected with more or less lip gaskets depending on the piston's travel at the desired pressure. The piston arrangement 1 has an internal pressure chamber 6 with a piston body 7. In FIG. 2, the piston body is shown in an intermediate position between the first and second outer positions.

The piston body 7 is provided with a gasket 21 which prevents the exchange between the internal pressure chamber 6 and the surroundings. The piston body 7 is provided with a tip 20 when the piston body 7 is in its first outer position, this tip 20 closes the opening 8 established in the piston surface 2 as the piston body 7 is displaced from the first outer position to the second outer position. The piston surface 2 is thus formed by the end of this tip 20 and the piston arrangement sheath 22, which encloses the piston body 7 with associated tip 20.

When the piston body is in its first outer position where the inner pressure chamber 6 has its smallest volume and there is no connection between the resin chamber 5 and the inner pressure chamber 6, the piston arrangement 1 can be used as the piston in the prior art.

When the piston body 7 is displaced from the first outer position towards the second outer position, it becomes possible to establish a negative pressure in the resin chamber 5 of a size which is not obtainable with the piston in the prior art. This allows the repairer to obtain a greater negative pressure, which in part gives a faster degassing of the resin and allows moisture and foreign matter to be extracted from the damage 17.

In FIG. 3-7 shows a piston arrangement which operates with the same principle as that of FIG. 2. When the piston body 7 is displaced from the first outer position to the second outer position, it becomes possible to establish a negative pressure in the resin chamber 5 of a size which is not obtainable with the piston in the technique known from US 3,993,520.

In FIG. 3 and 4, images of an embodiment of a piston arrangement are shown in separate and assembled condition.

The piston arrangement has an injection tube 4 similar to that shown in FIG. 2. This thus comprises the gasket member 3 which forms a resin chamber 5 defined by the piston surface 2 of the first piston body 32.

The first piston body 32 has the piston surface 2 provided by a first piston crown 33 which is provided for a sealing insert into the packing member 3. The second piston body 7 is slidably mounted in the casing 22 and has a second piston crown 35 which is in sealing abutment against the inside of the casing 22. . Hereby the pressure chamber 6 is formed with varying volume, which depends on the position of the other piston body in the sheath.

In this embodiment, an opening 8 is established in a side wall of the first piston body 32. The first piston body 32 is provided with sealing means 34 in the form of O-rings which seal against an inner wall of an O-ring 36 in an injection tube 4.

The aperture 8, which is in communication with an inner channel (discussed later in connection with Figures 5-7), is formed in the sidewall in a position between the sealing means 34 and the piston surface 2. The apertures 8 are thus provided at a distance from the piston surface which defines resinkammeret.

The first piston body 32 has in a region 38 between the opening 8 and the piston surface 2 a reduced diameter relative to the diameter of the part of the first piston body 32 on which the sealing means 34 are mounted. Thus, an annular chamber is formed between the piston body 32 and the inner channel 36 in the region 38. A visual indication (37) is arranged on the first piston body (32). In a flange 39 on the first piston body 32, an opening 40 is formed which serves to receive a tip 41 on a disposable syringe providing the second piston body 7.

FIGS. 5-7 show sectional views and a side view of the FIG. 3 and 4. Therefore, identical or similar elements will not be explained in detail in connection with these figures.

Figures 5-7 show that the opening 8 of the first piston body 32 is connected to an inner channel 42. The inner channel is connected to a bore 43 at the collar 40. The bore 43 serves to receive the tip 41 from the disposable syringe. In the region 38 together with an inner surface 44 of the injection tube, the first piston body 32 will form an annular chamber 45 which forms a connection between the aperture 8 and the resin chamber when the first piston body 32 is screwed to an outer position, as shown in FIGS. 7th

The sealing means 34 are positioned above the aperture 8 and thus ensure that the connection established via the annular chamber 45 and the aperture 8 as well as the duct 42 creates an airtight connection between the resin chamber 5 and the pressure chamber 6.

As can be seen from the figures, between the piston surface 2 defining the resin chamber 5 and the opening 8 there will be a distance corresponding to the height of the area 38. Thus, there is a very limited risk that resin will penetrate through the annular chamber 45 and contaminating the opening 8.

If, during use, a situation arises where resin has penetrated into the aperture 8 and the duct 42, the piston arrangement will very easily be blown clean by compressed air. When the first piston body 32 is unscrewed by the injection tube 4 and when the second piston body 7 is released, it will be very easy to blow compressed air into the bore 43 and remove any resin located in the duct 42 or the aperture 8, respectively.

Claims (9)

patent claims Piston arrangement (1) for use in repairing damage (17) to laminated glass (18), preferably a car window, by injection of resin, wherein the piston arrangement (1) comprises a first piston body (32) slidably disposed in a bore (36) in an injection tube (4) and having a first piston crown (33) with a piston surface (2) arranged for tightly sealing insertion into a gasket member (3) in the injection tube (4) enclosing said gasket member (3) a resin chamber (5), said piston arrangement (1) further comprising a second piston body (7) slidably disposed in a sheath (22) and having a second piston crown (35) in sealing abutment against the sheath (22). inside, forming an inner pressure chamber (6) which varies in volume depending on the position of the second piston body (7) in the casing and in which an opening (8) is formed in the first piston body (32) which establishes a connection between the resin chamber (5) and the internal pressure chamber (6), characterized by that sealing means (34) are arranged on the first piston body (32) which seals against an inner wall of the bore (36) and that the opening (8) is formed in the side wall of the first piston body (32) in a position between the sealing means (34) and the piston surface (2). Piston arrangement according to claim 1, characterized in that the connection between the resin chamber (5) and the internal pressure chamber (6) is closed when the piston body (7) is in a first outer position where it is pressed into the bottom of the injection tube (4) and that the connection is established when the first piston body (32) is offset from a first outer position at such a distance that the piston surface (2) is brought out of the tightly sealed insertion into the gasket member (3). Piston arrangement according to claim 1 or 2, characterized in that the piston arrangement (1) has an outer thread (9) complementary to an internal thread (10) in the injection tube (4). Piston arrangement according to any one of the preceding claims, characterized in that the first piston body (32) has a reduced diameter in a region (38) between the opening (8) and the piston surface (2). Piston arrangement according to any one of the preceding claims, characterized in that the sealing means (34) comprise at least one and preferably two O-rings. Piston arrangement according to any one of the preceding claims, characterized in that a visual indication (37) is shown on the first piston body (32) showing that the piston surface (2) is brought out of the sealing insertion into the packing means. (3). Piston arrangement according to any one of the preceding claims, characterized in that the external threads (9) of the piston arrangement (1) are provided on the first piston body (32). Piston arrangement according to claim 7, characterized in that the visual indication (37) is a colored ring on the outer thread (9) of the first piston body (32) and that it is positioned so that it becomes visible outside the injection tube when the piston surface (2) is brought out of the tight-fitting insertion into the gasket member (3). Piston arrangement according to any of the preceding claims, characterized in that the piston arrangement (22) of the piston arrangement and the first piston body (32) are releasably connected. 1.4 20B 13 14 11Ä 11B