EP3360648A1 - Pressure generator with two pneumatic pistons - Google Patents

Abstract

The invention relates to a pressure generator, comprising a compressed air connection, a working as a pneumatic-hydraulic pump pressure booster with a pneumatic range and a hydraulic range, wherein the pressure generator is designed as a handheld device and has a self-closing hydraulic coupling for connecting a hydraulically operated tool application. According to the invention, the pressure booster on a pneumatic area with two pistons arranged in series, which are connected to a hydraulic piston.

Description

Field of the invention

The invention relates to a pressure generator, which is designed as a pneumatic-hydraulic pump and which is used in particular for a trained as a hand tool riveting, punching, pressing or drawing tool.

Furthermore, the invention relates to a riveting, punching, pressing or drawing tool, which is used in particular in the body area.

Background of the invention

The publication DE 10 2011 111 533 A2 (WSEngineering GmbH & Co. KG) shows a designed as a hydraulic-pneumatic pump pressure generator, which is used in particular for riveting, punching, pressing or drawing tools that are needed for bodywork.

The pressure generator is designed as a compact handheld device and comprises a quick coupling, via which a tool application, such as a riveting tool, can be connected to the pressure generator.

Via a compressed air connection, a pneumatic piston is driven to oscillate, which moves a hydraulic piston having a smaller diameter.

About the design of the piston surfaces can provide such a high transmission ratio that pressures of several 100 bar can be generated in a standard compressed air connection with a pressure of less than 10 bar in the hydraulic range. Due to the oscillating working principle, a sufficient amount of hydraulic fluid can be simultaneously moved to drive riveting, punching, pressing or drawing tools comprising a hydraulic working piston.

Already by this tool concept a universally functional tool could be provided, which has a sufficient force also in the processing of high-strength steels as well as of composite materials.

Object of the invention

The invention is based on the object to further improve the performance of a pressure generator and thus the performance of the pressure generator comprehensive riveting, punching, pressing or drawing tool.

Summary of the invention

The object of the invention is achieved by a pressure generator according to one of the independent claims.

Preferred embodiments and further developments of the invention can be found in the subject matter of the dependent claims, the description and the drawings.

The invention relates to a pressure generator.

The pressure generator is designed as a handheld device. Preferably, the pressure generator comprises a handle. In particular, the pressure generator comprises a handle with an actuating member.

The pressure generator comprises a compressed air connection.

Furthermore, the pressure generator comprises a working as a pneumatic-hydraulic pump pressure booster with a pneumatic range and a hydraulic range.

The pressure intensifier converts air pressure into hydraulic pressure. For this purpose, the pressure booster is designed as an oscillating pump, i. During a pulling or pushing operation, the pressure booster works as a pneumatic-hydraulic pump, with pneumatic and hydraulic pistons moving repeatedly. At each power stroke, hydraulic fluid is drawn from a buffer volume and conveyed via the hydraulic piston of the pressure booster at high pressure in the direction of a hydraulic connection for a tool application.

The pneumatic piston is formed larger than the hydraulic piston. About the ratio of the surface of the pneumatic piston and the surface of the hydraulic piston, the transmission ratio of the pressure booster is determined.

Furthermore, the pressure generator comprises a self-closing hydraulic coupling for connecting a hydraulically operated tool application.

The self-closing hydraulic coupling is in particular part of a quick coupling with which the tool application can also be mechanically connected to the pressure generator.

Under a hydraulically operated tool application is understood to be coupled to the pressure generator attachment, with which a forming operation by driving a hydraulic piston is possible. In particular, the tool application is designed for setting rivets or for punching holes.

The tool application thus includes itself a hydraulic piston which drives a pulling or pushing device. Thus, for example, an adapter for processing blind rivets with a pulling device can be placed as a tool application. Such a tool application for processing blind rivets includes claws with which a rivet pin is pulled. The pressing device can be designed, for example, as a rivet hoop for processing, in particular punched rivets, or as a punching device for punching holes.

According to the invention, the pressure booster comprises a pneumatic area with at least two pistons arranged in series, which are connected to a hydraulic piston.

Thus, the invention provides not only a piston for driving the hydraulic piston, but at least two pistons, which are arranged as a tandem piston in series one behind the other and with the hydraulic piston, for example. connected by a pole.

This means that the effective piston area can be almost doubled in a compact space.

The pistons run, in particular, in each case in a working space which can be acted upon with compressed air, the pistons being connected to one another via a rod which comprises a channel. Compressed air can flow from one working space to another working space via the duct.

It is provided in particular that in a working cycle of the pressure booster compressed air flows into a rear working space of at least one piston. From the rear working chamber, the compressed air flows through the channel in the rod in a front working space, so that both working spaces are pressurized with compressed air and advance the piston.

The front piston is in turn connected to the hydraulic piston, so that the hydraulic piston and the two pistons of the pneumatic area are rigidly connected in a row one behind the other.

In particular, a pressure generator with a pressure booster can be provided by the invention, which has a gear ratio of more of 1:50, preferably more than 1: 100.

The stroke of the pistons of the pneumatic range is preferably between 0.5 and 5 cm, more preferably between 1.5 and 3 cm.

In a further development of the invention, the hydraulic area can be acted upon by pneumatic pressure, in that compressed air compresses a membrane or displaces a piston.

In particular, a valve is provided, via which in a first actuation stage of the pressure generator the hydraulic area is acted upon only with pneumatic pressure, without compressed air being introduced into the working chambers of the pistons.

At the self-closing hydraulic clutch then hydraulic fluid is at a pressure which corresponds only approximately to the pressure of the compressed air.

Thus, a fast feed can be provided in a simple manner, in which the pulling or pushing device of a coupled tool application is moved with such little force that it comes to a halt as soon as the movable part of the tool application encounters resistance, in particular if the movable part of the Tool or an associated rivet comes into contact with the sheet.

This has the advantage in press devices that, in particular in the case of a bow-shaped tool application, the movable part of the tool application can first be brought close to the sheet and then the user can correct the position again.

In traction devices, especially in tool applications with a pulling device for a blind rivet, the fast feed has the advantage that the component to be processed, in particular the rivet, can be held on the fast feed and there is no risk of falling out.

At the same time, due to the fast feed, the intensifier must be set in motion only for the actual deformation process, but not only for advancement until sheet metal contact exists. As a result, the wear, in particular the wear of seals of the hydraulic area, in which a very high pressure prevails, can be reduced.

In particular, pressures of more than 500 bar, preferably more than 700 bar, can be produced by the pressure intensifier according to the invention.

In a preferred embodiment of the invention, the pressure generator comprises a bypass valve, via which hydraulic fluid can flow back to a working space of a membrane or a piston.

The bypass valve is in particular designed such that it automatically opens when releasing an actuator. This allows the oil to flow back into the pressure generator, wherein a membrane or a piston in a working volume provides the necessary buffer volume for this purpose.

The hydraulic piston of the tool application is automatically reset when you release an actuator, which improves the safety of the tool.

In a further development of the invention, the pressure booster comprises a piston control with a valve for influx of compressed air into the working spaces, which is actuated in a zero position by one of the pistons so that compressed air flows into the work spaces and after exceeding a control bore, the compressed air flow out of the work spaces leaves.

This valve is arranged in particular in the working space of a first piston and is actuated by the piston resting on the valve.

By the then incoming compressed air, the two pistons are moved forward in one stroke. In a disfigurement, one of the pistons, in particular the first piston in relation to the incoming compressed air, passes over a control bore, via which compressed air flows from the working space through a channel to the valve and the valve is opened, so that the compressed air flows out of the work spaces and the pistons reset by, for example, by a spring to be moved back to the zero position and the next power stroke begins.

Such a piston control can be achieved high power values. In particular, the compressed air supply is closed in the working space when resetting the piston. This increases performance while reducing compressed air consumption.

The invention further relates to a pressure generator, in particular a pressure generator, as described above. The pressure generator comprises a compressed air connection, a working as a pneumatic-hydraulic pump pressure booster with a pneumatic range and a hydraulic range and is also designed as a handheld device and has for connecting a hydraulically operated tool application on a self-closing hydraulic coupling.

According to the invention, the pressure generator comprises a channel via which compressed air leaving the working chamber of a pneumatic piston flows into a rear-side chamber of the piston.

The effluent at each stroke compressed air, which in particular after exceeding a control bore again flows out of the work or the rooms is therefore not directly discharged, but is directed into a chamber which faces the working space of the piston.

It thus creates the back of the piston pressure, which at least supports the reset of the piston or.

Further, the compressed air can expand in the chamber before it is discharged for example via a silencer.

As a result, the noise emission of the pressure generator according to the invention can be significantly reduced at the same time in a simple manner.

In particular, it is provided that the compressed air connection is located in a rear region of the pressure generator, wherein the compressed air from the working space of the piston is passed over at least one, preferably two, running next to the working space channels in the back chamber of the piston.

Due to the lateral channels which extend in the housing parallel to the working space or the work spaces, the dimensions of the pressure generator hardly increase.

Already these channels contribute to the soundproofing.

The invention further relates to a riveting, stamping, pressing or drawing tool, which comprises a pressure generator described above, wherein a tool application is connected to the self-closing hydraulic coupling, which in turn has a hydraulic piston for driving a pushing or pulling device.

Brief description of the drawings

• Fig. 1 ist eine perspektivische Ansicht eines Ausführungsbeispiels eines erfindungsgemäßen Druckerzeugers.
• Fig. 2 ist eine Schnittansicht des in Fig. 1 dargestellten Druckerzeugers.
• Fig. 3 ist eine perspektivische, teils aufgeschnittene Ansicht des in Fig. 1 und Fig. 2 dargestellten Druckerzeugers.
• Fig. 4 und Fig. 5 zeigen beispielhafte Werkzeugapplikationen für den in den Zeichnungen Fig. 1 bis Fig. 3 dargestellten Druckerzeuger.

The object of the invention will be explained in more detail below with reference to an embodiment.

• Fig. 1 is a perspective view of an embodiment of a pressure generator according to the invention.
• Fig. 2 is a sectional view of the in Fig. 1 shown pressure generator.
• Fig. 3 is a perspective, partially cutaway view of the in Fig. 1 and Fig. 2 shown pressure generator.
• Fig. 4 and Fig. 5 show exemplary tool applications for the in the drawings Fig. 1 to Fig. 3 shown pressure generator.

Detailed description of the drawings

Fig. 1 is a perspective view of an embodiment of a pressure generator 1 according to the invention.

The pressure generator 1 is designed as a handheld device and comprises a housing 2 with a rear compressed air connection 9.

On the opposite side of the compressed air connection 9 is a quick coupling 5 with a self-closing hydraulic valve. 4

The pressure generator 1 comprises a handle 3 with an actuating member 6 in the form of a switch.

Depending on how deep the actuator 6 is pressed, the pressure generator 1 can be switched to a first and a second stage.

In a first stage 4 hydraulic fluid is in a connected to the pressure generator 1 tool application via the quick coupling 5 with the self-closing hydraulic valve (see FIG. 5 and FIG. 5 ).

As a result, in a first stage of the hydraulic piston 39, 49 of the tool application is moved until it encounters a resistance.

The user can switch the actuator 6 by deeper pressures in a second stage, in which a much higher pressure, in particular at least ten times higher pressure in the hydraulic region 14 is generated, so then then from the coupled tool application a forming process, in particular a rivet or Punching process, can be performed.

Fig. 2 is a sectional view of the in Fig. 1 illustrated pressure generator 1.

Also in this view, the actuator 6 on the handle 3 of the pressure generator 1 can be seen.

The actuator 6 is locked by a safety switch 7, which must be actuated simultaneously to depress the actuator 6.

Evident is the arranged on the quick coupling 5 hydraulic valve 4. This is self-closing trained and establishes a hydraulic connection to a connected tool application.

The pressure generator 1 comprises a compressed air connection 9.

In this embodiment, the compressed air connection 9 leads to a pressure control valve 10, which is designed in particular as an upstream pressure limiter.

The actuator 6 acts on a valve 11, which is formed in this embodiment as a 5/2-way valve.

In a first stage, upon actuation of the actuator 6, the valve 11 is moved into a switching state, so that via a channel 15 compressed air can flow into a chamber in which a membrane 16, which is formed in this embodiment as a cylindrical bag, can flow , Alternatively, instead of a diaphragm, a piston could be used (not shown).

The chamber within which the membrane 16 is arranged, is part of the housing 2 of the pressure booster. 1

Hydraulic fluid can then flow in the direction of the hydraulic area via the channel 17. The hydraulic fluid first flows into the annular channel 40.

The hydraulic fluid flows via the suction valve 33 to the hydraulic valve 4.

The membrane 16 settles in their working space until the hydraulic piston of a connected tool application comes to rest.

In the hydraulic region 14, the extent of which is approximately indicated by the dashed line, a pressure prevails in this operating state which is approximately equal to, say, any pressure losses, e.g. by a counter tension of the material of the membrane 16, the applied pneumatic pressure corresponds.

As a result, a small force is generated by the tension or compression device of the connected tool application, which is not yet sufficient to start a forming process.

Since the pressure intensifier described in detail below does not work for the fast feedrate executed in the first stage, the wear, in particular a seal 35, which seals the hydraulic area 14 with respect to the pneumatic area, is reduced.

The tool application can be connected to the quick coupling 5 by this is unlocked via the lever 34, the tool application is placed and then locked again via the lever 34.

The quick coupling 5 is formed in this embodiment as a rotatable coupling with a ball backdrop.

By a deeper pressing of the actuator 6 and the valve 11 is further depressed so that it now operates a preferably designed as a tilt valve 20 valve.

The valve 20 is arranged downstream of a pressure regulator 12, via which the voltage applied to the pressure booster pressure via the pressure control valve 10 is controllable. The voltage applied behind the pressure control valve 10, which drives the pressure booster, can be read on the pressure gauge 43.

The entire pneumatic area 13 is also outlined with a dashed line.

The pressure generator 1 comprises a pressure booster, which in this embodiment comprises a tandem piston, consisting of the pistons 24 and 25, and a hydraulic piston 32 connected thereto.

In the second stage is compressed air via the valve 20 via the pressure regulator 12 preset pressure in the Passed channel 21, via which the compressed air flows into the working space 22 of the piston 24.

The piston 24 is connected via a rod 41 with a channel 26 with a second piston 25, in the working space 23 also compressed air flows.

The pistons 24, 25, which form a tandem piston, are connected to the hydraulic piston 32, which sucks hydraulic fluid via the suction valve 33 and delivers it at high pressure in the direction of the hydraulic valve 4 via the pressure valve 42, which only allows the hydraulic fluid to pass in one direction.

The pistons 24 and 25 are thus initially pushed at a power stroke by the compressed air flowing into the working chambers 22 and 23, wherein the effective piston area is almost doubled by the two pistons 24, 25.

This makes it possible to provide a transmission ratio of more than 1:80, preferably more than 1: 100, with at the same time compact dimensions. At the same time, a high delivery rate can be achieved. This can be twice as high or even higher with the same ratio.

At the end of a power stroke of the piston 24 passes over a control bore 27th

Via the compressed air flowing into the channel 28, a control valve 29, which is designed as a pilot control piston, is opened, which on the one hand interrupts the supply of compressed air into the working spaces 22 and 23 and on the other hand and the compressed air from the compressed air flows out of the working spaces 23, 24 leaves.

In contrast to many pressure intensifiers known from practice, therefore, when the pistons 24, 25 are reset, the compressed air supply into the working chambers 22, 23 is completely interrupted. This increases the performance of the tool and reduces the compressed air consumption.

Via a return spring, the pistons 24, 25 are now moved back into an initial position. The return spring, not shown here sits in the back chamber 31st

The compressed air present in the work spaces 22, 23 now flows through at least one channel 30 (not visible here) at least into a rear-side chamber 31 of the piston 25, and preferably also via a channel into a rear-side chamber of the piston 24.

As a result, the resetting of the pistons 24, 25 is supported on the one hand.

On the other hand, the compressed air can first relax in the chamber 31 before it is discharged, which considerably improves the noise damping of the pressure generator 1 according to the expansion silencer principle.

If the piston 24 is fully reset, it sets on the control valve 29, the control valve 29 closes again and it starts a new power stroke, in which again compressed air flows into the working chambers 22, 23.

Thus, the pressure booster formed by the pistons 24, 25 and the hydraulic piston 32 together with control works as an oscillating pump and pumps via the suction 33 and pressure valve 42 hydraulic fluid at high pressure.

At the end of a forming process, the pressure booster 1 stops, for example because the hydraulic piston of a tool application can not be moved further.

If now the user lets go of the actuating member 6, compressed air is led into the working chamber of the bypass valve 19 via the valve 11 via a channel (not shown).

The bypass valve 19 opens and via the channel 18, the hydraulic fluid can flow back into the hydraulic region 14 of the pressure generator 1, so that the piston of the tool application is reset.

For a compressed air failure, the bypass valve 19 can also be actuated manually via a relief lever 8, so that the user can reset the tool even without applied compressed air.

Fig. 3 is a perspective view of the pressure generator 1, wherein a front housing part is hidden.

It can be seen in this view, in particular, that the air flowing from the working chambers 22 and 23 is first guided over at least one channel 30, preferably via a plurality of channels 30, forward, ie in the direction of the quick coupling 5, and then only via a preferably with a silencer provided outlet 37 enters the outside.

Via the lateral channels 30, the compressed air flows into the rear chamber 31 of the piston 25, where it can expand. The compressed air then flows out of the chamber 31 via at least one channel 44, preferably via two channels 44, to the outlet 37, preferably to two outlets 37. The channel 30 to be seen in this view is closed by the housing part hidden in this view. Preferably, the channel 30 has a branch through which compressed air in a rear chamber of the piston 24 flows when resetting the piston 24, 25.

Fig. 4 shows a tool application in the form of an attachable adapter for processing blind rivets, ie a Blindnietapplikation 36th

The Blindnietapplikation 36 includes a pulling device with the claws 45, with which the tool pulls on the pin of a blind rivet until it transforms. At the end of the riveting operation, the pin tears off.

The Blindnietapplikation 36 is connected by means of the self-closing hydraulic coupling 38 to the quick coupling 5 of the pressure generator 1 and includes a hydraulic piston 39 which is moved in the working space 51 to the rear, thereby actuating the claws 45 of the pulling device.

After releasing the actuator 6 of the pressure generator 1, the hydraulic piston 39 is reset by the spring 46 and the volume of hydraulic fluid which has flowed into the working chamber 51, via the hydraulic coupling 38 back into the pressure generator 1. Here, the membrane 16 serves as a buffer volume.

Particularly advantageous in the use of such Blindnietapplikation 36 is that by means of actuation of the first stage, the pulling device already grasps the pin of the blind rivet and holds so that there is no risk that it accidentally falls out.

Fig. 5 shows a Nietapplikation 47, for example, for processing two-piece rivets, which is designed as a pressing device.

This includes a head 48 for insertion of a rivet. By way of the hydraulic piston 49, which can be reset via the spring 50, the head piece for processing a rivet, for example, can be pressed against a rivet bracket (not shown) attached to the rivet application 47, which, for example, carries the counterpart of a two-part rivet.

Punching tools are also usually bow-shaped and comprise a similarly configured pressing device.

It is particularly advantageous that, by using the pressure generator 1 according to the invention, the movable part of the tool application connected to a hydraulic piston of the tool application, that is to say e.g. the head piece 48, any forward and backward and can be aligned, without already a forming process is started.

The handling of a riveting, punching, pressing or drawing tool according to the invention could thus be significantly improved. At the same time, the wear, in particular the wear of the seals in the hydraulic area could be substantially reduced.

LIST OF REFERENCE NUMBERS

1

pressure generator

2

casing

3

Handle

4

hydraulic valve

5

quick coupling

6

actuator

7

safety switch

8th

release lever

9

Compressed air connection

10

Pressure control valve

11

Valve

12

pressure regulator

13

pneumatics

14

hydraulics

15

channel

16

membrane

17

channel

18

channel

19

Bypass valve

20

Valve

21

channel

22

working space

23

working space

24

piston

25

piston

26

channel

27

control bore

28

channel

29

control valve

30

channel

31

chamber

32

hydraulic pistons

33

suction

34

lever

35

poetry

36

Blindnietapplikation

37

outlet

38

hydraulic connection

39

hydraulic pistons

40

annular channel

41

pole

42

pressure valve

43

manometer

44

working space

45

steal

46

feather

47

Nietapplikation

48

headpiece

49

piston

50

feather

51

working space

Claims (12)

Pressure generator, comprising a compressed air connection, working as a pneumatic-hydraulic pump pressure booster with a pneumatic range and a hydraulic range, wherein the pressure generator is designed as a hand-held device and has a self-closing hydraulic coupling for connecting a hydraulically operated tool application,
characterized in that the pressure booster comprises a pneumatic area with two pistons arranged in series, which are connected to a hydraulic piston. Pressure generator according to the preceding claim, characterized in that the pistons each run in a pressurizable compressed air working space, wherein the pistons are connected to each other via a stage comprising a stage, via which compressed air can flow from one working space into the other working space. Pressure generator according to one of the preceding claims,
characterized in that the pressure intensifier has a transmission ratio of more than 1:50, preferably of more than 1: 100. Pressure intensifier according to one of the preceding claims,
characterized in that the stroke of the pistons is between 0.5 and 5 cm, preferably between 1.5 and 3 cm is. Pressure generator according to one of the preceding claims,
characterized in that the hydraulic area can be acted upon by pneumatic pressure by compressed air compresses a membrane or displaces a piston. Pressure generator according to one of the preceding claims,
characterized in that the pressure generator has a bypass valve, via which hydraulic fluid can flow back to a working space of a membrane or of the piston. Pressure generator according to one of the preceding claims,
characterized in that the pressure booster comprises a piston control with a valve, which is preferably designed as a pilot control piston, which is opened after exceeding a control bore and the compressed air can flow to the work spaces, the valve closes the compressed air supply into the work spaces when resetting the piston. Pressure generator according to one of the preceding claims,
characterized in that the self-closing hydraulic coupling part of a quick coupling, via which the tool coupling is firmly connected to the pressure generator. Pressure generator, in particular according to one of the preceding claims, comprising a compressed air connection, working as a pneumatic-hydraulic pump pressure booster with a pneumatic range and a hydraulic range, wherein the pressure generator is designed as a hand-held device and has a self-closing hydraulic coupling for connecting a hydraulically operated tool application, characterized that the pressure generator comprises a channel, flows through the compressed air leaving the working chamber of a pneumatic piston in a rear chamber of the piston. Pressure generator according to the preceding claim, characterized in that the compressed air connection is located in a rear region of the pressure generator, wherein the compressed air is guided from the working space via at least one running next to the working space channel in the rear chamber of the piston. Pressure generator according to the preceding claim, characterized in that the compressed air is conducted from the working space in a front region of the pressure generator to the outside, preferably via a silencer. Riveting, punching, pressing or drawing tool, comprising a pressure generator according to one of the preceding claims and a tool application connected to the self-closing hydraulic coupling, which in turn has a hydraulic piston for driving a pushing or pulling device.

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