EP1731272A2 - Pneumatic knocker and method of operating a pneumatic knocker - Google Patents

Abstract

The knocking-out device has a first compression cavity (27) with a compressed air connection, and a second compression cavity between the cover (15) and the striker piston (9) in a cylindrical tube (2). The cover contains at least one aperture (19), through which compressed air is supplied to the second compression chamber, with the aperture sealed by the piston in its end position.

Description

The invention relates to a pneumatically operated knocker and a method for operating a pneumatically operated knocker.

Pneumatically operating knockers are used in particular for tapping off caking from a container wall. It may, for example, the tapping of dust-like material from a container wall act. Such tapping has been found to be useful and possibly necessary when the dust-like material is not entirely dry and also prone to bridging or sticking. By a strong blow against the outer wall of the container, the dusty material can be loosened or dissolved and made to flow out.

A pneumatically operated knocker and a method for operating a pneumatically operated knocker is from the DE 38 19 112 A1 known. In such a knocker of the percussion piston is moved away by applying an overpressure in the first pressure chamber of the striking plate or the container wall and in this case biases a between the percussion piston and the lid, strong spring before. This spring comes after reversing a valve associated with the first cylinder chamber in the venting position, the task to move the percussion piston abruptly against the impact plate or the container wall and thus to cause the knock. An arranged in the lid quick exhaust valve vents the first pressure chamber to the spring receiving the second pressure chamber, so that the air leaving the first pressure chamber is transferred into the second pressure chamber and, with a small force component, the spring force superimposed.

The disadvantage of this knocker that it is designed quite complicated. Thus, the spring is to be provided, which is to be arranged between the percussion piston and the lid, further, integrated into the lid, to provide the quick exhaust valve. The production cost of this knocker and the assembly effort is therefore significant. Considering that hard impact forces are exerted by means of the knocker, the number of individual parts of the knocker results in an increased susceptibility to failure since each individual component of the knocker is subjected to a high force introduction and vibration stress.

A similarly designed pneumatically operated knocker with arranged between the percussion piston and the lid spring is out of DE 38 19 111 A1 known.

A pneumatically operated knocker with spring is further in the DE-PS 25 49 551 described. In this, the air line between the first pressure chamber and the second pressure chamber is guided outside the cylinder tube.

In the US 4,070,947 a pneumatically operated knocker and a method for operating a pneumatically operating knocker is described, in which a cylinder tube is used to guide a percussion piston, wherein the cylinder tube is closed with a lid and between the percussion piston and the lid, a pressure chamber is formed. This lid is provided with an opening which is connected to a compressed air connection. The cover plate has the task to limit the pressure chamber and to serve as a stop for the percussion piston. The percussion piston does not seal the opening in its end position moved away from the impact plate. The process of the piston in the direction of the impact plate is effected by opening a valve and thus concerns an increased pressure on the percussion piston, and directly with respect to the entire piston surface.

The object of the invention is to provide a pneumatically operated knocker and a method for operating a pneumatically operated knocker, which ensures that the percussion piston for performing the knocking abruptly the piston is subjected to this moving force for applying the blow.

The problem is solved concerning the pneumatically operating knocker by the features of claims 1 and 2 and concerning the method for operating the pneumatic knocker by the features of claims 14 and 15.

The percussion piston is thus moved away by the pending in the first pressure chamber low pressure of the object to be tapped until it seals the at least one opening in the lid. The relatively high pressure in the region of the at least one opening in the lid is then applied to the partial surface of the percussion piston which is assigned to the opening and defined by the sealing of the striking plate and lid, which is substantially smaller than the cross-sectional area substantially corresponding to the internal cross-sectional area of the cylinder tube the impact piston, thus much smaller than the entire cross-sectional area of the percussion piston. As a result, initially, at the upcoming relatively high pressure, a relatively small force acts on the percussion piston. The actuation of the percussion piston is triggered either only by this relatively high pressure or, advantageously, by the venting of the first pressure chamber. Due to the pressure reduction in the first pressure chamber, the force acting on the percussion piston in this area is reduced, so that the high pressure prevailing in the second pressure chamber, despite the lower pressure surface, generates on the percussion piston such a counterforce that is greater than the force due to of the pending in the first pressure chamber pressure on the percussion piston acts. Consequently, the percussion piston is moved out of its sealing position, whereby now the relatively high overpressure acts on the entire cross-sectional area of the percussion piston so that it is abruptly moved in the direction of the striking plate or the container wall or of the object to be tapped and abuts against it and in this case causes the knocking process.

Valves that are assigned to the compressed air connections to the two pressure chambers are controlled so that when applying the relatively high pressure on the percussion piston the first pressure chamber is vented, so that the percussion piston must not be moved against an increased pressure in the first pressure chamber. The moving back of the percussion piston against the lid by reversing the compressed air connection of the first pressure chamber and in particular venting the second pressure chamber, wherein a relatively low pressure in the first pressure chamber is applied. This pressure is just so high that the percussion piston can be moved to the position for sealing the opening in the plate.

If the second pressure chamber is not vented when the high pressure is applied in the first pressure chamber, it is disadvantageous that work must be carried out against the pressure in the second pressure chamber. It is advantageous, however, that the control effort is significantly simplified, because in the second pressure chamber is always present a constant pressure and the movement of the percussion piston takes place only by the variably controlled pressure in the first pressure chamber. An additional available air space below the stepped piston still has the advantage that when hitting the entire air must not be forced out of this area of the housing. It can thereby build up a very high pressure below the percussion piston, and the impact energy is fully utilized when hitting the percussion piston on the clubface.

The relatively low overpressure according to method step a) of claims 14 and 15 is for example 0.5 to 1.0 bar. The relatively high overpressure according to method step b) of claims 14 and 15 is for example 4 to 10 bar, preferably 5 to 7 bar, in particular 6 bar.

The inventive method makes it possible to realize different heights of the knocker in a simple manner. It is a construction of the knocker with a relatively long displacement of the percussion piston conceivable.

In particular, in knockers in which a large height is acceptable, the method for operating the knocker can be designed so that the relatively high pressure is not directly adjacent to the opening in the lid, but a lid upstream pressure accumulator is provided in the manner of a third pressure chamber , which is connected to the compressed air connection. In this case, in the third pressure chamber, a relatively large volume at a relatively high overpressure is available for moving the percussion piston. - On the other hand the knocker is very flat. In such a case is dispensed with the third pressure chamber, thus the pressure accumulator. A sufficiently sized valve takes over the task of the accumulator here.

The knocker may be designed differently, in particular in the region of the lid, with respect to the at least one opening. Various openings can be provided in the lid, which are sealed by means of the percussion piston in its end position moved away from the striking plate or container wall or the article to be tapped. According to a preferred embodiment of the knocker according to the invention, it is provided that the lid has a single central opening which is arranged concentrically to the central longitudinal axis of the lid.

The knocker according to the invention is characterized by few moving parts. Basically, it is only necessary to move the percussion piston. When using a striking plate this is preferably mounted displaceably in the longitudinal direction of the cylinder tube in this. If no impact plate is present, the impact piston thus acts directly on the container wall, it must be ensured that the first pressure chamber of the knocker is sealed with respect to the container wall.

Preferably, the pneumatic knocker is used for knocking off caking from a container wall. It is also conceivable to use the knocker to tap components to vibrate them. In the latter case, the percussion piston is preferably led out of the housing.

In principle, the percussion piston can be made very simple, with a substantially flat, surface facing the lid, which is also flat on this side. The lid passes through the at least one opening, so that it is only necessary to provide a seal between the lid and percussion piston. This is preferably done by elastic seals, which are embedded in the percussion piston and / or the lid, for example by an O-ring surrounding the single central opening.

The knocker can be made particularly inexpensive if it consists of very simple items. This can be realized easily with the knocker. Thus, the cylinder tube is designed as a commercially available tube. It takes in the region of its end facing the container wall on a flange for attachment to the container. Inside the tube, the impact plate can be stored. The percussion piston is to be designed according to the internal dimensions of the commercial tube. The lid is designed as a plate-shaped body, in the simplest way with the one central opening. The lid may be positioned against an extension in the tube and fixed axially by means of a circlip, with a seal interposed between the lid and the tube sealing these parts to one another. Optionally, may be formed on the side facing away from the container of the lid, the third pressure chamber, which is closed by a cover plate which is connected to the pipe end. This cover plate is provided with the compressed air connection for the relatively high overpressure. The pressure connection in the first pressure chamber takes place laterally through a bore in the pipe, wherein in this area the percussion piston is tapered, so that when applying the relatively low pressure, a resultant force component in the longitudinal direction of the tube results, which is sufficient, the percussion piston of the impact plate or to move the container wall away, in the sealing position with respect to the opening in the lid.

The need for operating the knocker valves and pressure regulator can be part of the knocker, thus integrated into this or completely detached from the actual knocker.

Of particular importance in the knocker according to the invention or the method according to the invention for operating the knocker is that the area ratio of the cross-sectional area of the percussion piston to the cross-sectional area the percussion piston, which is acted upon in a sealed opposite opening in the lid, with quite a few smaller openings can be provided, is quite large. Already with minimal displacement of the percussion piston from the sealing position with respect to the lid, ie the formation of a minimum gap between the seal between percussion piston and lid of the upcoming relatively high pressure on the entire cross-sectional area of the percussion piston is effective, so that the percussion piston abruptly this moving force Accelerating the percussion piston is exposed. In the method according to the invention, the movement of the piston from the sealing position by the venting of the first pressure chamber is triggered or by increasing the pressure in the opening associated with the second pressure chamber until this force is greater than the counteracting force, via the first pressure chamber on the piston acts. With minimal travel of the percussion piston this can suddenly be exposed to this moving pressure force because the seal between the percussion piston and cover is canceled and consequently the pending in the second pressure chamber relatively high pressure now abruptly over the entire cross-sectional area of the percussion piston is effective. In this connection, a preferred design of the knocker provides that the cover and the percussion piston have faces arranged in parallel on the mutually facing sides. Furthermore, the lid facing the end face of the percussion piston and / or the percussion piston facing end face of the lid serves to receive a ring seal. This is in particular at a small distance from the opening, arranged concentrically to this.

The pneumatically operated knocker is structurally very simple and easy to install. It consists in particular of only a few components; Furthermore, the knocker is less susceptible to interference.

Further features of the invention are set forth in the subclaims, the description of the figures and the figures themselves, wherein it is noted that that all individual features and all combinations of individual features are essential to the invention.

Figur 1

eine Seitenansicht einer ersten Ausführungsform des pneumatisch arbeitenden Klopfers,

Figur 2

eine Unteransicht des in Figur 1 gezeigten Klopfers,

Figur 3

eine Draufsicht des in Figur 1 gezeigten Klopfers,

Figur 4

einen Schnitt durch den Klopfer gemäß der Linie B-B in Figur 1,

Figur 5

einen Schnitt durch den Klopfer gemäß der Linie A-A in Figur 4,

Figur 6

eine Schnittdarstellung des Klopfers gemäß Figur 4, bei an der Schlagplatte anliegendem Schlagkolben, veranschaulicht mit den Ventilen und Druckreglern des Klopfers,

Figur 7

eine Schnittdarstellung des Klopfers gemäß Figur 6, veranschaulicht bei gegen den Deckel bewegtem Schlagkolben bei Abdichtung der zentralen Öffnung,

Figur 8

einen Klopfer in der Ausführungsform gemäß der Figuren 1 bis 7, allerdings unter dem Aspekt der Figur 6 bei modifizierter Ansteuerung der Druckräume des Klopfers,

Figur 9

eine zweite Ausführungsform des Klopfers, in einer Schnittdarstellung gemäß Figur 4,

Figur 10

eine dritte Ausführungsform des Klopfers, in einer Schnittdarstellung gemäß Figur 4 und

Figur 11

eine vierte Ausführungsform des Klopfers, in einer Schnittdarstellung gemäß Figur 4 oder Figur 7.

In the figures, the invention is illustrated by various embodiments, without being limited thereto. It shows:

FIG. 1

a side view of a first embodiment of the pneumatic knocker,

FIG. 2

a bottom view of the knocker shown in Figure 1,

FIG. 3

a top view of the knocker shown in Figure 1,

FIG. 4

a section through the knocker according to the line BB in Figure 1,

FIG. 5

a section through the knocker along the line AA in Figure 4,

FIG. 6

4 is a sectional view of the knocker according to FIG. 4, with an impact piston resting against the striking plate, illustrated with the valves and pressure regulators of the knocker,

FIG. 7

3 is a sectional view of the knocker according to FIG. 6, illustrated with a percussion piston moved against the cover when the central opening is sealed,

FIG. 8

a knocker in the embodiment according to the figures 1 to 7, but in the aspect of Figure 6 with modified control of the pressure chambers of the knocker,

FIG. 9

a second embodiment of the knocker, in a sectional view according to Figure 4,

FIG. 10

a third embodiment of the knocker, in a sectional view according to Figure 4 and

FIG. 11

A fourth embodiment of the knocker, in a sectional view according to Figure 4 or Figure 7.

With regard to the description of the first embodiment of the pneumatically operating knocker 1, reference is first made to the illustration of FIGS. 1 to 7:

The knocker 1 is used in particular the tapping of caking of a container wall. He has as a central component on a cylinder tube 2, which is designed as a commercial, pressed in continuous casting tube. The cylinder tube 2 is screwed in the region of its one end in a mounting flange 3, which is bolted to the container wall, not shown, wherein the surface 4 of the mounting flange 3 rests against the container wall. The mounting flange 3 has a plurality of through holes 5 for the insertion of fastening screws. In the region of the mounting flange 3, the cylinder tube 2 passes through a striking plate 6, which is sealed by means of a sealing ring 7 against the inner wall 8 of the cylinder tube 2. The striking plate 6 is thus arranged in the region of the container wall and displaceable in the axial direction of the cylinder tube 2. On the side facing away from the container wall of the impact plate 6, a percussion piston 9 is slidably mounted in the cylinder tube 2 in the axial direction of the cylinder tube 2. This has a central cylindrical portion 10, a the impact plate 6 facing frusto-conical portion 11 and a sealing ring 39 which is inserted on the side facing away from the striking plate 6 of the cylindrical portion 10 in a concentric with the cylinder tube axis Aufnahmeringnut 12 of the section 10.

From the impact plate 6 facing away from the end of the cylinder tube 2, an intermediate ring is used in this, which has the function of a lid 15. This is applied to a recess 16 of the cylinder tube and is axially fixed by means of a locking ring 17. A sealing ring 18 seals the plate-shaped cover 15 to the inner wall of the cylinder tube 2 out. The lid 15 is provided with a respect to the longitudinal center axis of the cylinder tube 2 concentric opening 19 which passes through the lid 15.

The diameter of the sealing ring 39 accommodated in the cylindrical portion 10 of the percussion piston 9 is slightly larger than the diameter of the opening 19 in the lid 15. The lid 15 and the cylindrical portion 10 have end faces arranged in parallel on the mutually facing sides on. The sealing ring 39 thus seals the percussion piston 9 with respect to the lid 15 in the immediate vicinity of the opening 19. This results in a large area ratio between the (total) cross-sectional area of the percussion piston 9 (and thus the inner cross section of the cylinder tube 2) and the cross-sectional area, which is enclosed by the sealing ring 39 (and consequently only slightly larger than the cross-sectional area of the opening 19, the the partial area of the cross-sectional area of the percussion piston 9 represents).

The lid 15 is placed, starting from the surface of the container 4 associated with the container, approximately in the transition from the second to the third third of the length of the cylinder tube 2. The impact plate 6 facing away from the end of the cylinder tube 2 is closed by means of a further lid, which is referred to as a cover plate 22 for distinction. This is screwed into the cylinder tube 2. The cover plate 22 is provided with a central, continuous threaded bore 23 for connecting a compressed air connection 24. Further, the cylinder tube 2, adjacent to the mounting flange 3, is provided with a radially extending threaded bore 25 for a compressed air connection 26. This opens in the area in the interior of the cylinder tube 2, which faces the frusto-conical portion 11 of the percussion piston 9, in the case of impact plate 2 resting against the container wall 2 and impact plate 9 lying against the impact plate 6.

In the embodiment illustrated in FIGS. 1 to 7, the threaded bore 25 forms the air inlet for the piston chamber, whereas the threaded bore 23 forms the air inlet for the pressure reservoir of the knocker. In this respect, Figure 6 illustrates the percussion piston 9 in its one end position, when resting against the impact plate 6. Figure 7 illustrates the percussion piston 9 in its other end position, in which the sealing ring 39 sealingly rests on the cover 15. In this sealing position according to FIG. 7, a first pressure chamber 27 is formed between the percussion piston 9 and the striking plate 6. In the case of contact of the percussion piston 9 on the impact plate 6, however, a second pressure chamber 28 is formed between the percussion piston 9 and the lid 15.

As can be seen from the illustration of FIG. 6 with regard to this first embodiment, the compressed-air connection 26 has a compressed-air source 29, a pressure regulator 30 and a 3/2-way valve 31. The pressure regulator 30 regulates the pressure which is present at the first pressure chamber 27 to 0.5 to 1 bar. Accordingly, the compressed air connection 24 is provided with a compressed air source 32, a pressure regulator 33 and a 3/2-way valve 34. The pressure regulator 33 regulates the pressure which is present in the third pressure chamber 35 formed between the cover 15 and the cover plate 22 to 6 bar.

• In einem ersten Schritt wird das Ventil 31 betätigt. Der Schlagkolben 9 wird durch die einströmende Luft nach oben gedrückt, durch den sehr geringen Druck von 0,5 bis 1 bar. Der zweite Druckraum 28 und der dritte Druckraum 35 sind zu diesem Zeitpunkt entlüftet.
• In einem zweiten Schritt hat der Schlagkolben 9 seine Endlage erreicht, wie es in der Figur 7 veranschaulicht ist, und es ist die der Öffnung 19 zugeordnete Bohrung im Deckel 15 abgedichtet. Das Ventil 34 wird betätigt, der dritte Druckraum 35 wird unter Druck von ca. 6 bar gesetzt, abhängig von dem im ersten Druckraum 27 vorhandenen Luftdruck und dem Querschnitt der Öffnung 19 im Deckel 15. Während des Ladevorganges ist das Ventil 31 noch offen.
• Im dritten Schritt wird das Ventil 31 entlüftet. Die Luft im ersten Druckraum 27 entweicht über das Ventil 31. Der Schlagkolben 9 bewegt sich und es wird bei minimalem Hub des Schlagkolbens 9 die Dichtwirkung zwischen diesem und dem Deckel 15 aufgehoben. Schlagartig steht der in den zweiten Druckraum 28 einströmenden Luft jetzt die gesamte Kolbenquerschnittsfläche zur Verfügung und der Schlagkolben 9 wird mit hoher Kraft beschleunigt. Das Ventil 34 sollte während des Schlagvorgangs geöffnet bleiben, so dass noch Luft nachströmen kann.
• Im vierten Schritt wird das Ventil 34 geschlossen und es werden der zweite Druckraum 28 und der dritte Druckraum 35 entlüftet. Der Schlagvorgang ist beendet, und dann kann der Zyklus von Neuem beginnen.

The pneumatic knocker 1 described so far is operated, for example, as follows:

• In a first step, the valve 31 is actuated. The percussion piston 9 is pressed by the incoming air upwards, by the very low pressure of 0.5 to 1 bar. The second pressure chamber 28 and the third pressure chamber 35 are vented at this time.
• In a second step, the percussion piston 9 has reached its end position, as illustrated in FIG. 7, and the bore 19 associated with the opening 19 is sealed in the cover 15. The valve 34 is actuated, the third pressure chamber 35 is set under pressure of about 6 bar, depending on the present in the first pressure chamber 27 air pressure and the cross section of the opening 19 in the lid 15. During the charging process, the valve 31 is still open.
• In the third step, the valve 31 is vented. The air in the first pressure chamber 27 escapes via the valve 31. The percussion piston 9 moves and it is repealed at minimum stroke of the percussion piston 9, the sealing effect between this and the lid 15. Suddenly, the air flowing into the second pressure chamber 28 is now the entire piston cross-sectional area available and the percussion piston 9 is accelerated with high force. The valve 34 should remain open during the impact process, so that still air can flow.
• In the fourth step, the valve 34 is closed and the second pressure chamber 28 and the third pressure chamber 35 are vented. The beating process is over and then the cycle can start again.

The valves 31 and 34 and the required pressure regulator 30 and 33 may be part of the knocker 1, thus be integrated, or be completely detached from the actual knocker.

Figure 8 illustrates a modified control of the pressure chambers of the knocker 1. The process is basically off, as described for Figure 6, but now with automatic actuation of the valve 34. The valve 34 is by the use of a throttle 36 in a compressed air connection 37, the Compressed air connection 26 connects with the control of the valve 34, actuated with a time delay. The actuation of the valve 34 may only take place when the percussion piston 9 has reached its voltage applied to the lid 15 end position. The throttle 36 thus serves to switch on and off delayed switching of the valve 34. The components can, as before, part of the knocker or completely detached.

The embodiment according to FIG. 9 is characterized in that the third pressure chamber 35 has been dispensed with. The knocker 1 builds more compact, consequently with a shorter cylinder tube 2, the end facing away from the mounting flange 3 directly receives the lid 15. The third pressure chamber 35 is replaced in this case by the specially dimensioned valve 34, which ensures the supply of a sufficiently large air mass flow into the second pressure chamber 28 in the corresponding switching position. The control and regulation of the knocker 1 takes place in this embodiment corresponding to that according to the embodiment of FIG. 6.

The embodiment of Figure 10 is basically formed according to the embodiment of Figures 1 to 8, but it is characterized by the flat design, ie at further shortened cylinder tube 2, but which has a much larger diameter.

The stroke of the percussion piston should be selected according to the dimensions of the knocker. It is for example 10 to 150 mm, preferably 30 to 80 mm, in particular 50 to 60 mm. The diameter of the piston can vary very much. There are very small variants with a piston diameter of 10 mm to large variants with a piston diameter of 1m conceivable.

The calculation of the pressures in the pressure chambers and the diameter of the opening in the cover and the entire cross-sectional area of the impact piston can be done in a simple manner taking into account the physical equations. If the weight of the percussion piston is ignored, the assumption of an equilibrium of forces on the piston by the forces acting in the pressure chambers as a prerequisite for triggering the movement of the percussion piston 9 by venting the pressure chamber 27 results in the following physical relationships in the sense of the inscription in FIG 7: $$\frac{d_1}{{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">d</figure-callout>}}_2}=\frac{\sqrt{p_2}}{\sqrt{{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="imgf0001.png"\; state="\{\{state\}\}">p</figure-callout>}}_1}}$$

There is thus a dependence of the quantities d ₁ , d ₂ , p ₁ and p ₂ given.

If, for example, pressures p ₁ = 0.5 bar and p ₂ = 6.0 bar and a diameter d ₁ of 70 mm are specified as prerequisites, the diameter d ₂ must be 20.21 mm in order to keep the percussion piston 9 in equilibrium. If the first pressure chamber 27 is vented, thus the pressure p _{1 is} lowered, a larger force acts on the cross-sectional area with the diameter d ₂ than on the cross-sectional area with the diameter d ₁ , so that the percussion piston 9 is moved in the direction of the first pressure chamber 27. From the above equation, it is obvious that when three parameters are specified the diameter d ₁ or the pressure p ₁ or the pressure p ₂ can be calculated.

The embodiment according to FIG. 11 operates on the same principle of operation as that according to FIG. 7. Components which correspond in their mode of operation to this embodiment are designated by the same reference numbers in FIG. 11 for the sake of simplicity.

In the embodiment of FIG 11, the assembly for receiving the percussion piston 9 no cylinder tube 2, but a housing 40. This housing 40 consists of the two housing parts 41 and 42, which are screwed together by means of several screws 43. In the housing 40, corresponding to the circumstances in a cylinder tube 20, a space for receiving the percussion piston 9 is formed. In a recess of the housing part 42 of the lid 15 is mounted. The lid 15 is fixed axially between the two housing parts 41 and 42. In the housing part 42 between the latter and the lid 15 of the third pressure chamber 35 is formed, further between the lid 15 and the percussion piston 9 of the second pressure chamber 28, finally between the percussion piston 9 and in the region of the housing part 41 which faces away from the lid 15, In contrast to the embodiments described so far, in the embodiment according to FIG. 11 the percussion piston 9 has, in addition to the actual piston section 44 which can be brought into operative connection with the cover 15, a further piston section 45 with a smaller diameter, which has a corresponding diameter Opening 46 in the housing part 41 passes through sealing. The seal is effected by means of sealing rings 47. The piston portion 44 is sealed by means of sealing rings 48 with respect to the housing part 41. Concentric with the opening 19, the lid 15 is provided with the O-ring 39. The third pressure chamber 35 is provided with the threaded bore 23 for the purpose of compressed air connection and the pressure chamber 27 with the threaded bore 25 for the purpose of compressed air connection. The passage 19 in the lid 15 is, starting from the pressure chamber 35, designed as a conically tapered truncated cone.

This described embodiment is used in particular to tap a component. Thus, the housing part 42 is provided with a threaded bore 49 for attaching the knocker 1 to a frame part, not shown. Also, the lid 15 facing away from the end of the percussion piston 9 is provided with a threaded bore 50 with which in particular a plastic part is connected, which is moved when knocking against the component. The leadership of the percussion piston 9 serves not only the housing part 41 in the region of the sealing rings 48, but also an aligned on the piston portion 44 annular projection 51 of the housing part 41. When moved away from the cover 15 percussion piston 9 abuts this with its associated with this plastic part on the to be knocked component. In order, if there is no object to be knocked in the area of the knocker 1, to prevent the percussion piston from being moved widely, the projection 51 of the housing part 41 is provided as a stop, an annular elastic element 42 cushioning the movement of the percussion piston 9. The pressure chamber 27 includes an annular air reservoir / residual volume 53. During the movement of the percussion piston 9 for the purpose of hitting the air volume in the first pressure chamber 27, d. H. the existing air must escape via the bore 25. It has been shown that shortly before impact of the percussion piston 9 on the object to be tapped or the projection 51 an air cushion between percussion piston 9 and housing part 41 is formed frontally. In this embodiment, it is therefore not necessary to remove all the air from the first pressure chamber 27.

The knocker according to the embodiment according to FIG. 11 is operated, for example, so that permanently a relatively low pressure prevails in the pressure chamber 27, which is suitable for pressing the percussion piston 9 in the direction of the cover 15, provided that a lower pressure prevails in the pressure chamber 35. For example, the first pressure chamber 27 is permanently exposed to an overpressure, with a value of the overpressure between 0.5 and 2 bar being considered particularly suitable. If a relatively high pressure is applied to the pressure chamber 35, leads this in that the sealing of the cover 15 and percussion piston 9 in the region of the sealing ring 39 is released and thus the high pressure can abruptly attack on the much larger cross-sectional area of the percussion piston 9, which corresponds to the diameter of the pressure chamber 28. The percussion piston 9 is further moved against the still in the pressure chamber 27 pending pressure. If, after the knocking process has been carried out, the pressure in the pressure chamber 35 and thus in the pressure chamber 28 is reduced again, the striking piston 9 is pushed back against the sealing ring 39 of the cover 15 due to the pressure constantly present in the pressure chamber 27.

Claims (22)

Pneumatically operating knocker (1), with a cylinder tube (2) sealed with a striking plate (6) or the container wall and with a cover (15), and a percussion piston (9) movable in the cylinder tube (2) to form a first pressure chamber ( 27) between impact plate (6) and percussion piston (9) or container wall and percussion piston (9), wherein the first pressure chamber (27) has a compressed air connection (26), and for forming a second pressure chamber (28) between the cover (15) and percussion piston (9), wherein the lid (15) is provided with at least one opening (19) and the second pressure chamber (28) through the at least one opening (19) can be acted upon with compressed air, wherein the surface of the at least one opening (19) smaller is as the piston cross-sectional area, wherein the percussion piston (9) in its moved away from the striking plate (6) or the container wall end position, the opening (19) seals. Pneumatically operating knocker (1), with a by a percussion piston (9) and a lid (15) closed housing part (41), wherein the percussion piston (9) in the housing part (41) is movable and an opening (46) in the housing part (41 ), penetrated to form a first pressure space (27) between the housing part (41) and percussion piston (9), wherein the first pressure chamber (27) has a compressed air connection (26), and for forming a second pressure chamber (28) between the cover (15 ) and impact piston (9), wherein the lid (15) is provided with at least one opening (19), and the second pressure chamber (28) through the at least one opening (19) can be acted upon with compressed air, wherein the surface of the at least one opening (19) is smaller than the piston cross-sectional area, wherein the percussion piston (9) seals the opening (19) in its cover-side end position. Knocker according to claim 1 or 2, wherein the percussion piston (9) in its lid (15) facing the end position sealingly against the cover (15) Knocker according to one of claims 1 to 3, wherein the lid (15) has a single, in particular central opening (19). Knocker according to one of claims 1 to 4, wherein the lid (15) is formed as a plate. Knocker according to one of claims 1 to 5, wherein the cover (15) or the percussion piston (9) at a distance from the opening (19), in particular at a small distance from the opening (19) concentric with the opening (19) has a seal (39). for sealing against the percussion piston (9) and the cover (15). Knocker according to one of claims 1 to 6, wherein the cover (15) and the percussion piston (9) on the mutually facing sides arranged in parallel end faces. Knocker according to claim 7, wherein the cover (15) facing the end face of the percussion piston (9), and / or the percussion piston (9) facing the end face of the lid (15) of receiving a ring seal (39). Knocker according to one of claims 1 and 3 to 8, wherein between the cover (15) and the cylinder tube (2) in the region of the impact piston (9) facing away from the end cap closing plate (22), a third pressure chamber (35) is formed, which a compressed air connection (24). A knocker according to any one of claims 2 to 8, wherein between the cover (15) and a further housing part connected to the housing part (41) (42) a with the second pressure chamber (48) connectable third pressure chamber (35) is formed, which has a compressed air connection (24). Knocker according to one of claims 1 to 10, wherein it has in the region of its first pressure chamber (27) a flange (3) for fastening to the container wall. Knocker according to one of claims 1, 3 to 9, 11, wherein the cylinder tube (2) is designed as a commercially available tube. Knocker according to one of claims 1 to 12, wherein in the lid (15) facing away from the end position of the percussion piston (9) of the first pressure chamber (27) has a residual volume (53). Method for operating a pneumatically operated knocker (1), wherein a percussion piston (9) is movable in a cylinder tube (2) which is closed with a striking plate (6) or the container wall and with a cover (15), which can be pressurized on both sides, and between the impact plate (6) or the container wall and the percussion piston (9), a first pressure chamber (27) with compressed air connection (26) and between the cover (15) and the percussion piston (9), a second pressure chamber (28), the compressed air is acted upon, formed, with the following features: a) moving the percussion piston (9) into a sealing position relative to at least one opening (19) in the cover (15) by applying a relatively low overpressure into the first pressure chamber (27) at a second, relatively unpressurized pressure chamber (28), b) subjecting the percussion piston (9), which seals the opening (19) in the cover (15), to a relatively high overpressure opening (19) in the area of a partial surface of the cross-sectional area of the percussion piston (9), c) moving the impact piston (9) from the sealing position and acting on the entire cross-sectional area of the percussion piston (9) with the relatively high pressure. Method for operating a pneumatically operated knocker (1), wherein in a closed with a cover (15) housing part (41) a percussion piston (9) is movable, which passes through an opening (46) in the housing part (41) sealed, wherein the percussion piston (9) can be acted upon on both sides with pressure, and between the housing part (41) and the percussion piston (9) a first pressure chamber (27) with compressed air connection (26) and between the cover (15) and the percussion piston (9) a second pressure chamber ( 28), which is acted upon by compressed air, is formed, having the following features: a) moving the percussion piston (9) into a sealing position relative to at least one opening (19) in the cover (15) by applying a relatively low overpressure into the first pressure chamber (27) at a second, relatively unpressurized pressure chamber (28), b) subjecting the percussion piston (9), which seals the opening (19) in the cover (15), to a relatively high overpressure opening (19) in the area of a partial surface of the cross-sectional area of the percussion piston (9), c) moving the percussion piston (9) from the sealing position and applying the entire cross-sectional area of the percussion piston (9) with the relatively high pressure. A method according to claim 14 or 15, wherein the movement of the piston (9) from the sealing position by the venting of the first pressure chamber (27) is triggered. A method according to claim 14 or 15, wherein the movement of the piston (9) from the sealing position by overpressure in the second pressure chamber (28), at pending pressure in the first pressure chamber (27) is triggered. Method according to one of claims 14 to 17, wherein the area ratio of cross-sectional area of the percussion piston (9) to the cross-sectional area of the opening (19) or the partial area of the cross-sectional area is large. Method according to one of claims 14 to 18, wherein in the method step a) the second pressure chamber (28) is vented. Method according to one of claims 14 to 19, wherein the relatively low pressure in accordance with method step a) 0.5 to 1.0 bar and / or the relatively high pressure in accordance with method step b) 4 to 10 bar, preferably 5 to 7 bar, in particular 6 bar is. Method according to one of claims 14 to 20, wherein the relatively high pressure in a third pressure chamber (35) is effective, wherein the second pressure chamber (28) and the third pressure chamber (35) by means of the opening (19) are interconnected. Method according to one of claims 14 to 21, wherein the first pressure chamber (27) is permanently subjected to a relatively low overpressure, in particular with an overpressure of 0.5 to 2 bar.

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