EP0408865B1 - Valve gun, in particular for high-pressure cleaning device - Google Patents

Abstract

In a valve pistol, particularly for a high pressure cleaning device, with a pistol housing (1) with a handle (2), with a valve (3) placed in the pistol housing (1) that is opened against the system pressure by a force transmission element that is displaced against a valve body (9) by a hand lever (12) that is mounted so that it can be pivoted on a pivot pin (11) in the pistol housing (1). The hand lever (12) can be pivoted over a certain pivoting path and has an actuating arm (13) that engages against the force transmission element (10). In accordance with a preferred embodiment, with little construction expense, it can be achieved that the holding force required on the hand lever (12) can be made as small as possible even when the valve body is opened, in that the pivot pin (11) is mounted in the pistol housing (1) or in the hand lever in a slot (14) extending approximately in the direction of movement of the force transmission element (10) and can be shifted in this slot, so that a shifting movement is partially superposed on the pivoting movement of hand lever (12) around the pivot pin (11), that the shifting movement of hand lever (12) is derived from its pivoting movement and for this purpose an effective drive connection, particularly a wedge-like connection is provided between the hand lever (12) and the pistol housing (1) or an L-shaped part for the pressure medium, and that a drive part is mounted on the hand lever (12) at a distance from the pivot pin (11) and a stationary support part, particularly a support roller (b 17), is installed on the pistol housing (1) or on the L-shaped part (6).

Description

The invention relates to a valve gun according to the preamble of claim 1.

The teaching of the invention relates generally to valve guns of the structure explained above, that is to say without being limited to the range of high-pressure cleaning devices. Nevertheless, to simplify the explanation, the teaching of the invention will now and in the following be explained using the example of a valve gun for a high-pressure cleaning device, in particular because the teaching of the invention is of particular importance for this area of application. Furthermore, the teaching of the invention is independent of whether the valve body of the valve is opened by pushing or pulling, that is to say whether a plunger or a pull rod, a pulling cable or the like is used as the force transmission element. Regardless of this, the power transmission element is sometimes also referred to below as a plunger, because force transmission elements designed as plungers are particularly widespread in valve guns of the type in question.

The known valve gun from which the invention is based (DE-A 3 518 492) has a ball valve with a spring-loaded valve ball as the valve body. When the valve body is closed, the essential force component is that from the system pressure. The opening force required when opening is the product of the system pressure and cross-sectional area of the valve seat. The required actuation force is reduced by the lever ratio on the hand lever. There is a lower limit for the lever ratio, which is determined by the available swinging force of the hand lever and the minimum required actuation path of the ram.

In contrast to other known valve guns, a large lever ratio is initially provided in the previously explained valve gun during the opening process; the actuating arm is very short compared to the hand lever. As a result, when the valve body is initially opened at a system pressure of, for example, 250 bar, the opening force can be reduced to 20 to 30 N instead of the previously known 100 N on the hand lever. By a second, after opening the valve in function pivot axis is achieved at the same time that when the valve body is open, the required holding force is as low as before, namely z. B is only about 10 N.

Otherwise, the holding force can be reduced even further when the valve body is open by working with a double lever reduction (DE-C 3 527 922) or using a toggle lever drive (GB-A 513 013). Both have considerable disadvantages, namely, they are extremely complex to construct and, at least in the case of the toggle lever drive, in turn leads to a loss of lever arm when the valve body is opened, that is to say to an increase in the opening force.

The invention is based on the object, the above-described, with regard to the opening force already very useful known valve gun with little design effort so that the hand force required when the valve body is open can be made as low as possible.

The above-mentioned object is achieved in a valve gun with the features of the preamble of claim 1 by the features of the characterizing part of claim 1. In a very simple way, namely by superimposing a displacement movement over the pivoting movement about the first pivot axis with the aid of a simple elongated hole / gear connection, the holding force can be minimized even when the valve body is open. The holding force can be made arbitrarily small by designing the gear connection, i.e. reduced to practically zero.

Fig. 1

teilweise im Schnitt, ein Pistolengehäuse einer erfindungsgemäßen Ventilpistole, geschlossener Zustand,

Fig. 2

den Gegenstand aus Fig. 1, druckentlasteter, also teilweise geöffneter Zustand,

Fig. 3

den Gegenstand aus Fig. 1, geöffneter Zustand,

Fig. 4

eine schematische Darstellung des Bewegungsablaufs verschiedener Teile einer erfindungsgemäßen Ventilpistole zum Zwecke des besseren Verständnisses des Funktionsprinzips und

Fig. 5

in schematischer Darstellung ein Ausführungsbeispiel eines für eine erfindungsgemäße Ventilpistole modifizierten Winkelrohrs.

Preferred refinements and developments of the teaching result from the dependent claims. For the rest, the invention is further described on the basis of the explanation of a preferred exemplary embodiment in conjunction with the drawing. In the drawing shows

Fig. 1

partly in section, a gun housing of a valve gun according to the invention, closed state,

Fig. 2

1, pressure-relieved, that is to say partially opened state,

Fig. 3

1, open state,

Fig. 4

a schematic representation of the sequence of movements of different parts of a valve gun according to the invention for the purpose of better understanding of the principle of operation and

Fig. 5

a schematic representation of an embodiment of an angled tube modified for a valve gun according to the invention.

The valve gun shown schematically in FIG. 1 is intended for a high-pressure cleaning device and initially has a gun housing 1, which in the exemplary embodiment shown here consists of plastic and is made of two half-shells or can also be formed in one piece. A handle 2 is formed on the gun housing 1 and a valve 3 is arranged in the gun housing 1. The valve 3 is located between a pressure medium connection 4 and an outlet connection 5, to which, for example, a spray lance (not shown here) can be connected. In the exemplary embodiment shown, the pressure medium connection 4 and the outlet connection 5 are integrated with one another in a single, continuous angled tube 6, in which the valve 3 is also arranged. The valve 3 opens against the system pressure, which is shown in the schematic illustration merely as an example as a spherical valve body 9 facing the pressure medium connection 4, loaded by a valve spring 7 in the closing direction and sealingly coming into contact with a valve seat 8. There are other ways of realizing this too. It is also shown that a plunger 10 is provided for opening movement of the valve body 9 against the spring force of the valve spring 7 and the closing force resulting from the system pressure on the valve body 9. The force transmission element 10, here designed as a plunger, serves to transmit force to the valve body 9 from a hand lever 12 which is pivotably mounted on the handle 2 on a pivot axis 11 in the gun housing 1.

As usual and as can be seen from a comparison of FIGS. 1, 2 and 3, the human anatomy allows only a certain, limited pivoting path for the hand lever 12. The hand lever 12 has an actuating arm 13 which comes into contact with the force transmission element 10, which in the exemplary embodiment shown is an integral part of the hand lever 12 itself, but also readily protrudes on the opposite side of the pivot axis 11 or lies at a somewhat measured angle with respect to the hand lever 12 can. Through the hand lever 12 and the actuating arm 13, a lever reduction with a certain lever ratio is realized for the actuation of the force transmission element 10.

For the purpose of a sufficient flow cross-section, the tappet 10 must be displaceable by the actuating arm 13 over a specific (minimum) actuation path when the valve body 9 is open. The lever ratio between the hand lever 12 and the actuating arm 13 is ultimately ultimately classically determined by the upwardly limited pivoting path of the hand lever 12 and the downwardly limited actuating path of the actuating arm 13.

From the comparison of Fig. 2 and Fig. 3 of the drawing, it follows that the hand lever 12 not only performs a pivoting movement about the pivot axis 11, but that this pivoting movement about the pivot axis 11 is partially superimposed on a displacement movement approximately in the direction of movement of the power transmission element 10. The pivot axis 11 of the hand lever 12 in the gun housing 1 (or the hand lever relative to the pivot axis) is namely essentially displaceable in the direction of movement of the force transmission element 10 over a certain distance. This is achieved here in that the pivot axis 11 is mounted in the gun housing 1 or in a separate support part in an elongated hole 14 which extends approximately in the direction of movement of the plunger 10 and is displaceable therein. Accordingly, the pivot axis could also be mounted in a corresponding elongated hole in the hand lever.

The displacement movement of the hand lever 12 must be initiated in some way. This is done here in such a way that the displacement movement of the hand lever 12 is derived from the pivoting movement and for this purpose an effective gear connection, in particular a wedge gear connection 15, is provided between the hand lever 12 and the gun housing 1 or the angle tube 6. Other gear connections, for example via a tension element, are also possible, but a wedge gear connection 15 is particularly simple to construct.

The drawing makes it clear that the transmission connection 15 can be implemented particularly expediently in that on the hand lever 12 at a distance from the pivot axis 11 a transmission part, in particular a gear roller 16, and on the gun housing 1 or on the angle tube 6 a stationary abutment part, in particular an abutment roller 17, is attached. It is obvious that corresponding roles as gear or abutment parts lead to rolling friction and thus to a lower coefficient of friction than pure sliders or the like.

4 makes the kinematic relationships clear from the schematic representation of the movement sequence in a particularly preferred exemplary embodiment. Only the head of the power transmission element 10 is shown, a closing protection insert 18 coming into contact with the head in the actuating arm 13, the pivot axis 11 in the elongated hole 14 as well as the gear roller 16 and the abutment roller 17. The position of the parts when the valve gun is closed is dot-dashed, with the valve gun relieved of pressure shown in broken lines and drawn through with the valve gun open. This corresponds to FIGS. 1, 2 and 3 of the drawing in the same order.

First of all, when the valve body 9 is closed, shown in dash-dotted lines, the force transmission element 10 assumes its uppermost position and the gear roller 16 with a little distance to the side of the abutment roller 17 lies, the effective distance of the abutment roller 17 to the pivot axis 11, ie the clear distance between the abutment roller 17 and the pivot axis 11, is less than the effective distance of the gear roller 16 to the pivot axis 11, ie here the distance between the center points. The lateral distance of the center of the pivot axis 11 from the center of the force transmission element 10 is relatively small, ie the lever ratio is relatively large. If a corresponding actuating force is now applied to the hand lever 12 in this position, the pivot axis 11 is pressed into the upper rounding of the elongated hole 14 and fixed therein and the hand lever 12 begins to pivot about the pivot axis 11. At the same time, the force transmission element 10 in FIG. 4 is pressed down, for example by a distance of approximately 1 mm. This movement is accompanied by a pivoting movement of the gear roller 16 about the pivot axis 11.

With the valve body 9 slightly open and thus largely relieved of pressure, the gear roller 16 now comes to bear laterally on the abutment roller 17. This situation is shown in dashed lines in FIG. 4, it is the pressure-relieved position of the valve body 9. The system pressure here has dropped to, for example, 200 bar. In addition, the restoring force on the valve body 9 only results from the effective cross-sectional area of the force transmission element 10. no longer from the effective cross-sectional area of the valve body blocking the valve seat 9. With further pivoting movement of the hand lever 12, the pivoting movement about the pivot axis 11 is now superimposed on a displacement movement in the direction of the longitudinal axis of the force transmission element 10, specifically in that the gear roller 16 on the abutment roller 17th rolls along with the hand lever 12 with simultaneous longitudinal displacement. The additional force required for this is not particularly large, at least less than the opening force to be initially applied.

On the one hand, the pivot axis 11 now moves downward in the elongated hole 14 in accordance with the rolling movement of the gear roller 16 on the abutment roller 17, so that a displacement of the hand lever 12 is produced parallel to itself, which leads to a corresponding longitudinal displacement of the force transmission element 10. On the other hand, there is only a slight pivoting of the hand lever 12 about the pivot axis 11, so that the effective actuating arm 13 for the force transmission element 10 is only slightly extended, even if the hand lever 12 performs a further pivoting movement.

The holding force with the valve body 9 open is already relatively low in this system. However, it can be reduced even further, to practically 0 N or even in the sense of self-retention. This is because the wedge gear connection 15 can be designed so that when the valve body 9 is open, it derives practically all of the restoring force caused by the force transmission element 10 into the stationary abutment. In the illustrated embodiment, the fact that when the valve body 9 is completely open, the gear part, in particular the gear roller 16, is in contact with the abutment part, in particular with the abutment roller 17, so that the contact point or the contact line is only slightly offset from the point of action or line of action of the Force transmission element 10 exerted restoring force on the abutment roller 17. In the exemplary embodiment shown, the abutment roller 17 is located exactly in the direction of alignment with the central axis of the force transmission element 10. Of course, this is not absolutely necessary. Rather, the previously explained mode of operation can also be achieved if the abutment roller 17 is in a completely different location, for example also beyond the pivot axis 11 lies. Even then there is a force flow path for the restoring force of the force transmission element 10, which ultimately ends at the indicated line of action in the abutment roller 17.

In Fig. 4 with "X" the slight offset is shown, which is still implemented here and which leads to the fact that it is ensured that the hand lever 12 always snaps back into the position in which the valve body 9 is closed. Nevertheless, the value "X" can be made 0 by corresponding arrangement of the abutment roller 17. If "X" even becomes "negative", so there is an offset to the other direction, then self-retention is realized when the valve body 9 is open. It has proven to be particularly expedient to choose the value "X" such that a residual holding force of 1 to 3 N results when the valve body 9 is open.

5 makes it clear, by way of example, how the abutment roller 17, on the one hand, and the pivot axis 11 in the elongated hole 14, on the one hand, can be integrated into a conventional valve gun with angled tube 6 in a very simple constructive manner. For this purpose, this angle tube 6 has a bearing bracket 19, which is attached to the angle tube 6, in particular welded on here. This has the advantage over the attachment to the gun housing 1 that the gun housing 1 can be kept free of forces.

Overall, the invention succeeds in an extraordinarily simple constructive manner in realizing an optimal force curve on the hand lever of a valve gun, namely to make the initial opening force as low as possible, nevertheless realizing the necessary opening travel for the valve body and at the same time practically holding the force when the valve body is open to be arbitrarily small. The lever ratio at the beginning of the opening movement can easily be increased to 1:12 to 1:20, since the required actuation path of the valve body of, for example, 3 mm is nevertheless achieved due to the superimposed displacement movement.

Claims (4)

1. A valve pistol, particularly for a high-pressure cleaning appliance, with a pistol housing (1) with a hand-grip (2), with a valve (3) disposed in the pistol housing (1) which is opened against the system pressure with a force transmission element (10) serving for the opening movement of a valve body (9), with a hand lever (12) swivel-mounted on a swivel pin (11) on the hand-grip (2) in the pistol housing (1), wherein the hand lever (12) can swivel over a certain swivelling distance and has an operating arm (13) which comes into contact with the force transmission element (10), wherein the force transmission element (10) can be moved by the operating arm (13) over a certain operating distance and wherein a certain lever ratio exists between the hand lever (12) and the operating arm (13), characterised in that the swivel pin (11) is mounted in the pistol housing (1) or in the hand lever in an elongated hole (14) extending approximately in the direction of movement of the force transmission element (10) and is movable in this elongated hole, so that a displacement movement is partially superimposed on the swivelling movement of the hand lever (12) with the operating arm (13) about the swivel pin (11), that the displacement movement of the hand lever (12) is derived from the swivelling movement and for this purpose a transmission connection, particularly a wedge transmission (15) is provided which acts between the hand lever (12) and the pistol housing (1) or an angled tube (6) disposed in and passing through the pistol housing (1), and that a transmission part, particularly a transmission roller (16), is provided on the hand lever (12) at a distance from the swivel pin (11), and a fixed abutment part, particularly an abutment roller (17), is provided on the pistol housing (1) or on the angled tube (6).
2. A valve pistol according to claim 1, characterised in that when the valve body (9) is closed the transmission part, namely the transmission roller (16) in particular, is situated at the side of and at somewhat of a distance from the abutment part, namely from the abutment roller (17) in particular, and the effective distance of the abutment part, namely of the abutment roller (17) in particular, from the swivel pin (11) is less than the effective distance of the transmission part, namely of the transmission roller (16) in particular, from the swivel pin (11), that when the valve body (9) is slightly open and thus substantially relieved of pressure the transmission part, namely the transmission roller (16) in particular, comes into contact with the side of the abutment part, namely with the abutment roller (17) in particular, and that on the further swivelling movement of the hand lever (12) the transmission part, namely the transmission roller (16) in particular, slides or rolls together with the hand lever (12) on the abutment part, namely the abutment roller (17) in particular, with simultaneous longitudinal displacement.
3. A valve pistol according to claim 1 or 2, characterised in that when the valve body (9) is fully open the transmission part, particularly the transmission roller (16), is seated against the abutment part, particularly against the abutment roller (17), so that the point of contact or the line of contact is situated only slightly displaced in relation to the point of application or the line of application of the restoring force exerted by the force transmission element (10) on the abutment roller (17).
4. A valve pistol according to any one of claims 1 to 3, characterised in that a mounting strap (19) for the swivel pin (11) and optionally for the abutment part, particularly the abutment roller (17), is secured to, particularly welded on to, the angled tube (6).

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