EP0052060B1 - Extrusion gun for pasty products stored in the form of standard cartridges - Google Patents

Abstract

1. Apparatus permitting the extrusion of a sealing compound or other paste contained in a cartridge (C) having a movable base, of the kind comprising a cylinder (28) to which a compressed gas is supplied in a continuous manner so as to cause the movable base of the cartridge to be displaced the neck of the cartridge issuing into a flexible tube (2) mechanically deformed by means of a trigger (13), characterised in that, the piston (4) of a single acting ram is associated with the tube (2) to crush it when the said ram is supplied with a flow of compressed gas derived from that which acts on the movable base of the cartridge (C), the said flow being returned to the ram in question as soon as the user releases the trigger (13), whilst the action of the latter causes the stopping of the said flow and the discharge of the said tube (2).

Description

The present invention relates to the extrusion of all pasty products such as sealants, glues, greases, etc. stored in standard cartridges.

To extract the products under consideration from their packaging, mechanical or compressed air guns are generally used which are intended to act on the movable bottom of the cartridge in order to move it axially.

When dealing with mechanical pistols the ejection of the product lacks precision. In addition, its use is difficult for a professional who must use a large number of cartridges. In addition the pressure on the trigger must be much stronger in winter when the product is a little frozen. After stopping the pressure on the trigger, the sealant continues to come out due to the pressure in the cartridge.

Air pistols produced by a compressor are also used. This type of gun wastes a large amount of air due to its operation. Indeed in order to neutralize the pressure exerted behind the movable bottom of the cartridge and in order to stop the output of the product clean it is necessary each time that the trigger is released to drain the air at the rear of the movable bottom of the cartridge. This requires the compulsory use of a compressor which delivers thousands of liters of compressed air without counting.

The major drawback of these guns is first of all the essential presence of a compressor which is not always very easy to transport, especially upstairs and whose operation is very noisy. In addition, stopping the outlet of the pasty product is not very clearly obtained because the emptying of the air under the movable bottom of the cartridge is not instantaneous. In general, the use of an air pistol is a very high cost price.

Such pistols are described in FR-A-1,508,882 and in French application 2,301,306.

In the first document according to the preamble of claim 1 it is shown that the outlet of the cartridge is associated with a flexible tube on the end of which is mounted the injector intended for the pouring of the pasty product. By moving a trigger, the tube is mechanically deformed to stop the spillage of the material. When the device has to be installed and that consequently the trigger is no longer actuated it is necessary to cut off the air supply under the movable bottom of the cartridge otherwise the pasty product continues to spill. This operation of course results in the emptying of the volume located under the movable bottom of the cartridge otherwise the pasty product would continue to spill even after closing the air supply due to the pressure prevailing in this volume.

In the second document, the rigid end piece with which the outlet of the cartridge cooperates is provided with a simple ball valve which opens or closes this end piece so that the material may or may not be ejected. Such a tap does not require the purge of the volume below the movable bottom of the cartridge but its manipulation of the tap leads on the one hand to the obligation for the user to use both hands and can on the other hand be counteracted in case of polymerization of the substance in the tap; in this case it can get stuck in the open or closed position.

The improvements which are the subject of the present invention aim to remedy these drawbacks and to ensure the production of a putty gun using only a very small amount of gas, which makes it possible to remove the compressor which is replaced by a small industrial nitrogen bottle. In addition, the gun according to the invention makes it possible, by operating a simple trigger, to close or open a flexible tip following the opening of the cartridge, this action being carried out pneumatically.

According to the invention, the piston of a single-acting cylinder is associated with the flexible end piece which follows the opening of the cartridge to crush it when said cylinder is supplied by a flow of compressed gas derived from the one which acts. on the movable bottom of the cartridge, said flow being sent into the jack considered as soon as the user releases a trigger, while the actuation of the latter causes said flow to stop and release the endpiece for allow the expulsion of the pasty product.

• Figure 1 est une vue en coupe d'un pistolet établi conformément à l'invention.
• Figure 2 est une vue par dessus de l'avant de ce pistolet.
• Figure 3 en est une coupe suivant A-A (fig. 2), montrant le vérin avant.
• Figure 4 est une vue semblable à celle de fig. 3 mais illustrant comment le vérin avant pince l'embout souple qui fait suite au débouché de la cartouche.
• Figure 5 est une vue en coupe de la partie arrière du pistolet suivant l'invention en position libre.
• Figure 6 est une vue semblable à celle de fig. 5 mais montrant la manière dont le fond de la cartouche coopère avec le dispositif de fig. 5.
• Figure 7 montre schématiquement le robinet à tiroir destiné à l'alimentation du vérin ouvert de fig. 5 et 6.
• Figures 8 et 9 en sont des coupes transversales qui illustrent le fonctionnement de ce robinet à tiroir.
• Figure 10 illustre en coupe la vanne d'alimentation du vérin montré en fig. 2 à 4, cette vanne étant en position d'alimentation du vérin avant.
• Figure 11 est une vue semblable à celle de fig. 7 mais illustrant la vanne en position de fermeture de l'alimentation du vérin avant.

The appended drawing, given by way of example, will allow a better understanding of the invention, the characteristics which it presents and the advantages which it is capable of providing:

• Figure 1 is a sectional view of a gun established in accordance with the invention.
• Figure 2 is a top view of the front of this pistol.
• Figure 3 is a section along AA (fig. 2), showing the front cylinder.
• Figure 4 is a view similar to that of FIG. 3 but illustrating how the front cylinder clamps the flexible end piece which follows the outlet of the cartridge.
• Figure 5 is a sectional view of the rear part of the gun according to the invention in the free position.
• Figure 6 is a view similar to that of FIG. 5 but showing how the bottom of the cartridge cooperates with the device of FIG. 5.
• Figure 7 shows schematically the slide valve for the supply of the open cylinder of fig. 5 and 6.
• Figures 8 and 9 are cross sections which illustrate the operation of this slide valve.
• Figure 10 illustrates in section the cylinder supply valve shown in fig. 2 to 4, this valve being in the supply position of the front cylinder.
• Figure 11 is a view similar to that of FIG. 7 but showing the valve in the closed position of the power supply to the front cylinder.

Illustrated in fig. 1 a device according to the invention comprising a frame 24 associated with a handle 15, said frame bearing on its part with a block 1 while its rear part receives an open jack 28.

The block 1 which is fixed to the front of the frame 24 by means of two screws 34, 35 (fig. 2) comprises a longitudinal bore la in which is engaged a flexible tube 2 comprising a tubular head 2a of larger diameter which is supported on the internal face of the block 1 by means of a collar 2b. The head 2a engages in a counterbore 1b of the block 1. The end of the tube 2 opposite its head 2a projects out of the block 1 and can receive a threaded ring 2c intended for example to receive a discharge tip not shown.

Another bore 1 c is formed in block 1 perpendicular to that ia. This bore opens out on the base of block 1 while its smaller diameter portion ends in bore 1a. The bore 1 receives a piston 4 whose head cooperates with the large diameter part of the bore 1c, its tail engaging in the smaller diameter part of said bore. A return spring 3 is provided so that in the free state the tail of the piston 4 is not in contact with the periphery of the flexible tube 2 (Fig. 3). Note the presence of a seal 5 at the periphery of the head of the piston 4 and another seal 6 disposed between the block 1 and the front part of the frame 24. This has a perforation 24a which ends up under the piston 4 via a channel 24b.

As illustrated in fig. 3 the neck of a cartridge C engages inside the tubular head 2a of the flexible tube 2, the seal between the cartridge and this tube being made by bearing the shoulder of the cartridge against the flange 2b.

Illustrated in fig. 4 the position of the piston 4 when compressed air arrives in the perforation 24 from a valve 8 fixed to the frame 24 at its handle 15. It is observed that the piston 4 moves upwards so that its tail pinches the flexible tube 2 in order to close it in a sealed manner as will be explained better below.

The rear part of the frame 24 supports an open jack, the cylinder 28 of which is secured to this part of the frame by a heel 14 and a transverse screw 31. The cylinder 28 is open in the direction of the block 1 and we have committed to inside the bore of this cylinder a piston 30 produced for example by means of an elastomer. The piston 30 comprises a peripheral lip 30a which cooperates in leaktight manner with the bore of the cylinder 28. This piston 30 constitutes a stop for a spring 29 which tends to push the said piston outwards from the cylinder 28. However, the race towards the exterior of this piston is limited by a screw 27, the head 27a of which bears in leaktight manner against a shoulder 30b of the center of the piston 30. A sealing washer R can moreover be associated for this purpose with the face of the 'shoulder 30b opposite the head 27a. Note the presence of two longitudinal holes 30c, 30d communicating the interior of the cylinder 28 and the exterior so that if the compressed gas arrives in the cylinder 28 when no cartridge is in place, there is a leak which prevents the reversal of the lip 30a.

The compressed air arrives in the cylinder 28 through a perforation 24c of the frame 24 connected to the interior of the cylinder considered by a slide valve 22 illustrated in FIG. 7. To this end, the frame 24 is provided with a transverse groove 24d, the bottom of which has a bore 24e ending in the perforation 24c (FIGS. 6 and 8). In the groove 24 is placed a flat drawer 34 comprising two extreme stops 34a, 34b which limit its axial movement, the distance between these two stops being greater than the length of the groove 24d. In a position of the drawer 34 the hole 24e of the frame 24 is in correspondence with an opening 34c of the drawer which itself comes opposite a hole 28a formed in the cylinder 28 (fig. 8) so that the compressed gas arriving through the perforation 24c penetrates under the piston 30. The top of the drawer 34 having a longitudinal groove 34d. When this drawer is subjected to translation, one of the ends of the groove 34d is brought opposite the hole 28a so that the inside of the cylinder 28 is placed in communication with the outside (FIG. . 9). Of course, seals 35, 36 are placed on either side of the drawer 34 respectively around the outlet of the holes 24e and 28a. Thus at the position of fig. 9 of drawer 34 the cylinder 28 is emptied.

The perforations 24a and 24c are supplied with compressed air from the valve 8 via pipes 25, respectively 21 (fig. 1). The valve 8 which is fixed below the frame 24 by means of a screw 7 comprises three channels 8a, 8b, 8c (fig. 10) in which the pipes 25 and 21 are fitted respectively, as well as a tube 19 the free end of which constitutes a nozzle to which the compressed gas supply is connected. It is observed that the channel 8c opens into that 8b so that the pipe 21 is supplied directly with gas. A blind stepped bore 8d is formed longitudinally in the valve 8. It is noted that the part with the smallest diameter of the bore 8d is in communication with the channel 8c, while the channel 8a opens into the part with the largest diameter of the said bore . Therein is engaged a valve 10 made in the form of a needle having a flange 10a. This valve leaves the valve 8 through a cable gland 33 so that its free end comes to cooperate with a trigger 13. A spring 18 pushes the valve outwards as illustrated in FIG. 1, 10 and 11. The flange 10a of the valve 10 is placed along the length thereof so that in the extended position, that is to say when the trigger is not actuated, the outlet of the channel 8a is located at the rear of this flange so that the gas entering the valve 8 through the tube 19 can flow into the channel 8a and the pipe 25 through the rear part of the bore 8d. We observes that an O-ring 11 is disposed between the flange and the gland 33 so that there is no leakage along the valve when it passes through said gland and that it is in position advanced. Similarly, an O-ring 12 is associated with the shoulder formed by the two diameters of the bore 8d as will be explained below.

When the trigger 13 is actuated, that is to say it is tilted about its axis 32 as illustrated in FIG. 11, the valve 10 which is moved axially against the reaction of the spring 18 is pressed in so that the flange 10a of this valve comes to bear against the seal 12. The supply of the pipe 25 is thus cut off without opposing that of the pipe 21. The gas contained in the bore 1 of the block 1 can therefore escape between the bore of the stuffing box 33 and the valve 10 because there is a large clearance between these two elements and that the seal 11 no longer plays any role.

When it is desired to use the device according to the invention, take a cartridge C containing putty or other pasty product, apply its base against the piston 30 and exert on it a force against the reaction of the spring 29 (fig. 6) so as to push this piston into the cylinder 28. We can then place the neck of the cartridge C inside the tubular head 2a of the tube 2 (fig. 3) and then releases the cartridge. The spring 28 applies the body thereof against the flange 2b of the tube to seal between the latter and the shoulder of the cartridge. Assuming that a compressed gas supply pipe is connected to the end of the tube 19, depending on the position of the drawer 34 the air arrives or not inside the cylinder 28. If this drawer is placed in the position of fig. 8 the gas arrives in said cylinder, passes through the annular space between the screw 27 and the central hole of the piston 30 as well as the holes 30c and 30d to come under the movable bottom of the cartridge in order to exert pressure on it . Similarly, the gas arriving through the pipe 25 actuates the piston 4, the end of which clamps the tube 2 so that the pasty product cannot exit the tube. If the user presses the trigger 13 the piston 4 is returned downwards by the spring 3 so that the tube is released and the product leaves the tube due to the air pressure on the movable bottom of cartridge C. Of course, the gas which has just acted on the piston is expelled towards the outside by passing through the annular space between the cable gland 33 and the valve 10.

A device has thus been produced which allows a substantial saving of compressed air, so that it can be supplied by means of a gas cylinder, in particular when the supply of compressed air is difficult, for example when the user is on the roof of a tall building.

Claims (9)

1. Apparatus permitting the extrusion of a sealing compound or other paste contained in a cartridge (C) having a movable base, of the kind comprising a cylinder (28) to which a compressed gas is supplied in a continuous manner so as to cause the movable base of the cartridge to be displaced the neck of the cartridge issuing into a flexible tube (2) mechanically deformed by means of a trigger (13), characterised in that, the piston (4) of a single acting ram is associated with the tube (2) to crush it when the said ram is supplied with a flow of compressed gas derived from that which acts on the movable base of the cartridge (C), the said flow being returned to the ram in question as soon as the user releases the trigger (13), whilst the action of the latter causes the stopping of the said flow and the discharge of the said tube (2).

2. Apparatus according to claim 1, characterised in that, the trigger (13) controls the valve member (10) of a valve (8) for supplying cir_lpressed gas to a single acting ram (1 c-4) provided in a block (1) situated at the front of the apparatus.

3. Apparatus according to claim 2, characterised in that, the end of the rod of the piston (4) of the ram crushes the tube (2) under the action of the compressed gas whereas when the gas is no longer present a spring (3) returns the piston (4) to release the said tube whilst the gas acting on the piston escapes through the supply valve (8) passing between the valve member (10) and its stuffing box (33).

4. Apparatus according to claim 1, characterised in that, the supply of compressed gas below the piston of the cartridge is effected by the agency of an open ram (28-30) the piston (30) of which is loaded by a spring (29) so that it acts on the base of the cartridge (C) to maintain its neck against a collar 2b of the tube (2) whilst ensuring the supply of air beneath the movable base of the said cartridge.

5. Apparatus according to claim 4, characterised in that, the neck of the cartridge (C) engages in a tubular head (2a) of the head (2) which is supported against the base of a facing (1 b) in the block (1) of the said apparatus.

6. Apparatus according to claim 4, characterised in that, the piston (30) of the open ram comprises a peripheral lever (30a) and a central opening traversed with clearance by a screw (27) of which the head, which limits the path towards the exterior of the said piston (30), closes in a fluid-tight manner the said passage when there is no cartridge in the apparatus and when it is supplied with gas whereas holes (30c, 30d) pass through the piston (30) so that if the compressed gas arrives in the cylinder (28) the latter is not put under pressure.

7. Apparatus according to any one of the preceding claims, characterised in that, a slide valve (22) is provided in the pipe (21) for supplying gas to the open ram.

8. Apparatus according to claim 7, characterised in that, changing the cartridge is effected by decompressing the gas behind the cartridge by actuating the slide (34) of the valve (22) and by slightly displacing the cartridge towards the rear so as to disengage its outlet from the mouth (2).

9. Apparatus according to claim 7, characterised in that, the slide (34) of the valve (22) comprises a position in which the interior of the cylinder (28) is in communication with the atmosphere.

Images