Pneumohydraulic pressure intensifier

Abstract

The invention relates to a pneumohydraulic pressure intensifier comprising at least one pneumatic piston coupled to a hydraulic pump. The pressure intensifier includes a regulator that can be used to adjust the hydraulic output pressure. The regulator is coupled to a hydraulic pilot control valve, which interrupts the air supply to the pneumatic piston when a set maximum pressure is reached.

Description

[0001] Pneumohydraulic pressure intensifier

[0002] Field of the invention

[0003] The invention relates to a pneumohydraulic pressure intensifier. In particular, the invention relates to a pneumohydraulic pressure intensifier designed as a handheld device that drives a pressing or pulling device, in particular a riveting, punching, or crimping device.

[0004] Background of the invention

[0005] Pneumohydraulic pressure intensifiers are known for generating high pressing and tensile forces. In particular, pressure intensifiers are known that oscillate a hydraulic pump with a suction and discharge valve, thus driving a hydraulic tool. Such a device can be compact and yet generate very high forces.

[0006] Patent EP 3 360 648 B1 (inventor Klaus Reitzig) shows such a pneumohydraulic pressure intensifier. To increase performance, this pressure intensifier includes a tandem piston. A pneumohydraulic pressure intensifier is also known from published patent application DD 70 011 A1.

[0007] Especially when such a pressure intensifier is used for a modular system with various tool attachments, it is necessary to adjust the maximum pressure of the pressure intensifier. The set maximum pressure is proportional to the pressing or pulling force of the tool. For example, with a riveting tool, the pulling or pressing force must be set to a specific value depending on the rivet used and the existing sheet pairing.

[0008] In the pressure intensifier described in the aforementioned patent, this is achieved using a pneumatic pressure regulator. The applied pneumatic pressure is adjusted on the pneumatic side of the pressure intensifier. The pneumatic pressure is proportional to the hydraulic pressure. Thus, the hydraulic pressure corresponds to the pneumatic pressure times the pressure intensifier's ratio. The ratio is the effective piston area of ​​the pneumatic piston(s) compared to the effective piston area of ​​the hydraulic piston.

[0009] Therefore, by reducing the pneumatic pressure, the hydraulic pressure and thus the maximum pressing or pulling force can be adjusted proportionally. A pneumatic pressure reducer is specifically designed as an upstream pressure limiter. However, with such a pressure limiter, the volume flow of compressed air decreases when the outlet pressure approaches the set maximum pressure.

[0010] This has been shown to reduce the performance of the pneumohydraulic pressure intensifier. In particular, the tool operates more slowly toward the end of the work cycle. This can also reduce the oscillation frequency of the hydraulic pump.

[0011] Object of the invention

[0012] The invention is based on the object of further increasing the performance of a pressure intensifier, which is used in particular as a drive for hydraulically operated tools.

[0013] Summary of the invention

[0014] The object of the invention is already achieved by a pneumohydraulic pressure intensifier according to one of the independent claims.

[0015] Preferred embodiments and further developments of the invention can be found in the subject matter of the dependent claims, the description and the drawings.

[0016] The invention relates to a pneumohydraulic pressure intensifier. This is particularly part of a pulling or pressing tool, in particular a riveting tool, punching tool, crimping tool, or cutting tool. For connecting to a tool application, the pressure intensifier can include a quick-release coupling. The pressure intensifier can be designed as a handheld device or as a stationary device.

[0017] The pressure intensifier comprises at least one pneumatic piston which is coupled to a hydraulic pump. The pressure intensifier operates in particular in an oscillating manner. For this purpose, the hydraulic pump can comprise a suction and a pressure valve. With each working stroke of the pneumatic piston, a hydraulic piston which is coupled to the pneumatic piston pumps hydraulic fluid. When the piston handle is reset, hydraulic fluid is drawn into the working chamber of the hydraulic piston via a suction valve, which is then pumped towards the tool application during the next working stroke. The hydraulic output pressure of the pressure intensifier can be limited. This can be done, for example, via an actuator, e.g. an adjustment wheel. As described above, the pushing or pulling force of the tool application connected to the pressure intensifier can be adjusted via a controller.According to the invention, the regulator is coupled to a hydraulic pilot control valve, via which the air supply to the pneumatic piston is interrupted when a set maximum pressure is reached.

[0018] According to the invention, the applied pneumatic pressure is not adjusted solely on the pneumatic side. Rather, the regulator allows the trigger pressure of a hydraulic valve to be adjusted. The hydraulic valve, in turn, is coupled to a pneumatic control valve, which interrupts the air supply to the pneumatic piston when the set maximum pressure is reached.

[0019] An inlet-side pneumatic valve, especially a main valve, can thus remain fully open throughout the entire work process. A pneumatic control line connected to the pilot control valve interrupts the air supply to the pneumatic piston when the maximum pressure is reached.

[0020] This allows the tool to operate at full power until the end of the work process. In particular, the frequency of the hydraulic pump can remain essentially constant.

[0021] The main valve can, for example, be designed as a 5 / 2 or 5 / 3 way valve.

[0022] In a further development of the invention, it is particularly provided that the main valve is designed in such a way that there are two stages when a trigger is pressed.

[0023] In a first stage, the hydraulic area is initially pressurized with pneumatic pressure without the hydraulic pump working.

[0024] This first stage can be used as a rapid feed, whereby the working piston of the tool application is advanced according to the pressure of the applied compressed air.

[0025] Then, in a second switching stage, the air supply to the pneumatic piston is opened, thus starting the pneumohydraulic pump.

[0026] According to a further aspect of the invention, it relates to a pneumohydraulic pressure intensifier, in particular as described above.

[0027] This consists of a pneumatic piston coupled to a hydraulic pump. The hydraulic pump delivers hydraulic fluid when the pneumatic piston is advanced.

[0028] In particular, the hydraulic pump operates in an oscillating manner as described above and comprises a pressure and a suction valve.

[0029] Furthermore, the at least one pneumatic piston can be reset via a control valve using pneumatic pressure. The pneumatic piston is therefore reset not by a spring, but by compressed air. In particular, it is provided that the control valve comprises a plunger, which is actuated by the pneumatic piston and then opens a channel through which compressed air flows into the working chamber to reset the pneumatic piston.

[0030] In a preferred embodiment of the invention, the pressure booster comprises a tandem piston with a first and a second piston. During a working stroke, the first and second pistons are advanced by introducing compressed air. In particular, the compressed air is introduced into the working chamber of the second piston and guided through a channel that connects the first and second pistons.

[0031] In one working stroke, both pistons work in parallel, driving the hydraulic pump. The tandem piston, however, can be reset by introducing compressed air into the working chamber of only the first piston.

[0032] When the piston is retracted, the hydraulic pump is not operating. Therefore, it is sufficient to supply compressed air into the working chamber of just one piston. This makes it easier to deploy the device with a simple design.

[0033] Preferably, a pneumatic control module is arranged between the working chamber of the first piston and the working chamber of the second piston.

[0034] In particular, it is provided that the pneumatic control module comprises channels through which compressed air can be alternately fed into the working chamber of the first piston and into the working chamber of the second piston.

[0035] Firstly, the compressed air is used to drive the hydraulic pump, particularly by both pistons during a working stroke.

[0036] On the other hand, the compressed air is directed into the other working chamber for resetting.

[0037] The control module can in particular comprise a control valve leading into the working chamber of a piston.

[0038] The control valve may in particular comprise a tappet which is actuated by the respective piston.

[0039] At the end of the working and reset cycles, the compressed air supply can be reversed via the control valves so that the compressed air now flows into the other working chamber.

[0040] Such a system is self-stabilizing and operates at a frequency determined by its design. This frequency can be between 10 Hz and 30 Hz. It is understood that the frequency depends, among other things, on the moving masses, the size of the working chambers, and the effective areas of the pistons involved. Switching the compressed air supply to the working chambers can be accomplished via a directional control valve, particularly a 5 / 2-way valve. The directional control valve can be controlled via control valves.

[0041] In particular, the directional control valve can comprise a slide valve, which is actuated by a control valve and thus switches the compressed air supply from one work chamber to the other. Preferably, an exhaust air duct is also opened or closed via the slide valve. Thus, when the slide valve is switched, the compressed air supply for one work chamber is opened and closed for the other; conversely, an exhaust air duct is closed for one work chamber and opened for the other.

[0042] In particular, it is provided that a central compressed air line leads to the slide valve and is alternately connected by the slide valve to the working spaces.

[0043] Control valves can, for example, actuate the slide mechanically.

[0044] Preferably, however, the control valves actuate the slide pneumatically. This type of pneumatic actuation is low-wear and reliable.

[0045] The control valves can be designed in particular as 2 / 2 or 3 / 2-way valves, which are each actuated via the piston moving in the working chamber.

[0046] Brief description of the drawings

[0047] The subject matter of the invention will be explained in more detail below using an exemplary embodiment with reference to the drawings Fig. 1 to Fig. 13.

[0048] Fig. 1 is a perspective view of a pressure intensifier.

[0049] Fig. 2 is a central longitudinal section.

[0050] Fig. 3 shows the pressure intensifier with the housing hidden.

[0051] Fig. 4 is a pneumatic equivalent circuit diagram.

[0052] Fig. 5 is a cross-section in the area of ​​the slide of the piston control.

[0053] Fig. 6 is a longitudinal section in the area of ​​the slide of the piston control.

[0054] Fig. 7 is a longitudinal section in the area of ​​the control valves of the piston control.

[0055] Fig. 8 is a longitudinal section of the tandem piston.

[0056] Fig. 9 and Fig. 10 are schematic representations of the piston control.

[0057] Fig. 11 is a cross-section illustrating the switching of the exhaust air.

[0058] Fig. 12 is an equivalent circuit diagram of the pneumatic piston control.

[0059] Fig. 13 schematically shows the relationship between volume flow and pressure according to a known pressure booster. Fig. 14 schematically shows the relationship between volume flow and pressure in the pressure booster according to the invention.

[0060] Fig. 15 is a longitudinal section of an exemplary tool application.

[0061] Detailed description of the drawings

[0062] Fig. 1 shows a perspective view of an embodiment of a pressure booster 1.

[0063] The pressure intensifier 1 is designed as a portable hand-held device and comprises a housing 2 with a handle 10, by which the pressure intensifier can be lifted and which comprises a trigger 11 for initiating a working process.

[0064] At the front, the housing 2 includes a hydraulic quick-release coupling 20. The hydraulic quick-release coupling 20 is used to connect a tool application (see Fig. 15). Furthermore, an actuator 201 is arranged on the housing 2. In this embodiment, the actuator 201 is designed as a rotary dial and serves as a regulator for setting the maximum working pressure. The pulling or pressing force of the tool application can be adjusted via the actuator 201. This is proportional to the hydraulic pressure generated by the pressure intensifier 1.

[0065] Fig. 2 is a central longitudinal section of the pressure intensifier 1.

[0066] The trigger 11 on the handle 10 actuates the pin 101 of a main valve 100 via a rod 12 in order to trigger a work process.

[0067] The quick coupling 20 comprises balls 22 as engagement elements for holding the tool application.

[0068] When locked, the balls 22 protrude through the openings of a cage 23.

[0069] The quick coupling 20 can be opened via a spring-loaded and axially displaceable locking ring 21.

[0070] Furthermore, the quick coupling 20 comprises a self-closing hydraulic valve 24.

[0071] In this embodiment, the initiation of a working process occurs in two stages. This is controlled by the main valve 100, which is preferably designed as a 5 / 3-way valve. If the user actuates the trigger 11 in a first stage, a pin 101 of the main valve 100 slides downwards, initially opening the control line 106 for rapid advance. The control line 106 applies pneumatic pressure to a diaphragm 30 filled with hydraulic fluid.

[0072] In the hydraulic area, especially at the quick coupling, a pressure is now present that corresponds to the pressure of the compressed air to which the pressure intensifier 1 is connected at the pneumatic connection 3. The tool application can thus be moved into position without initiating a work process.

[0073] If the user presses the trigger 11 into the second stage, the main valve 100 is actuated via the valve body 102 in such a way that compressed air flows from the inlet 105 via the outlet 104 to the piston control 500.

[0074] The pressure booster 1 shown here comprises a tandem piston 40 with two working chambers 41a, 41b, which are separated from each other by the piston control 500. The pistons 42a, 42b are coupled to each other via a connecting channel 43.

[0075] The tandem piston 40 drives a hydraulic piston 301 of the hydraulic pump 300.

[0076] The transmission ratio of the effective piston area of ​​the hydraulic piston 301 to the pneumatic pistons 42a, 42b is preferably over 100, in particular between 120 and 200. In this way, correspondingly high hydraulic pressures can be generated.

[0077] At the same time, a large volume of hydraulic fluid, in particular of over 50 cm3 , preferably from 80 to 500 cm 3 provided.

[0078] In this embodiment, the hydraulic pump 300 is designed as a single stage.

[0079] The hydraulic pump 300 comprises a pressure valve 302 and a suction valve 303. When the hydraulic piston 301 is advanced, the pressure valve 302 opens and pumps hydraulic fluid towards the tool application.

[0080] When the hydraulic piston 301 is reset, the pressure valve 302 closes the channel. At the same time, hydraulic fluid flows into the working chamber of the hydraulic piston 301 via the suction valve 303. This fluid is pumped forward during the next working stroke. The pressure intensifier 1 shown here is designed for two-hand operation and includes a lever 403, which the user must flip to initiate a work process. After the end of a work process, a relief valve 400 opens, opening a bypass that can only be closed again by flipping the lever 403, which is designed as an eccentric lever.

[0081] The relief valve comprises the spring 402, on which the spring body 400 is supported, which rests on a piston 404. The piston 404, in turn, is coupled to the lever 403 and can be moved against the spring force via the eccentric.

[0082] As already explained above, the maximum pressure is set via the actuator 201.

[0083] The pilot control valve 200 is used to adjust the working pressure.

[0084] The pilot control valve 200 includes a pin 202 that projects into the hydraulic area. In this embodiment, the relief valve 400 and the pilot control valve 200 share a common channel. This simplifies the manufacturing of the tool.

[0085] 200 and relief valve 400 are otherwise independent in their function.

[0086] The pin 202 is connected to a socket 203, which is part of a pneumatic control valve. The socket 203 rests on the spring 204. By turning the actuator 201, the preload of the spring 204 can be changed and thus the hydraulic pressure at which the pin 202 pushes the socket 203 towards the actuator can be adjusted.

[0087] 201 and thus closes the pilot control valve 200.

[0088] In this embodiment, the pilot control valve 200 is closed to terminate the work process. However, according to another embodiment, it is also possible for a pilot control valve to be opened.

[0089] As will be explained in more detail below, the pilot control valve 200 is coupled to the main valve 100 via a pneumatic line. If the pilot control valve 200 is triggered, the main valve 100 stops the compressed air supply to the piston control 500, thus ending the work process.

[0090] Fig. 3 is a perspective view of the pressure intensifier 1 with hidden housing components.

[0091] Shown are the pilot control valve 200 and the relief valve 400, which share a common hydraulic channel.

[0092] The hydraulic pump 300 includes a hydraulic line 305 at the front, which leads to the quick-release coupling 20. Furthermore, the hydraulic pump 300 includes a cover 304, which closes the working chamber of the piston 42b. A diaphragm 306, which provides additional hydraulic fluid, can be located in the working chamber of the piston 42b.

[0093] Between the two pistons 42a, 42b of the tandem piston 40, there are two control valves 50a, 50b in the piston control (500 in Fig. 2) as well as a directional control valve designed as a slide 504, which allows compressed air to flow alternately into the two working chambers.

[0094] The main valve 100 comprises the pin 101 as a trigger, a valve body 102 and a shut-off valve 103.

[0095] When actuated, compressed air flows from the outlet 104 towards the piston control.

[0096] Fig. 4 is a pneumatic equivalent circuit diagram showing the lines coming from and leading to the main valve 100.

[0097] The main valve 101 is coupled to the diaphragm 30 via a control line 106. In a first stage, compressed air is fed into the working chamber of the diaphragm 30 via the control line 106, thus subjecting the hydraulic area to the pressure of the applied compressed air.

[0098] Furthermore, the main valve 100 is coupled to the relief valve 400 via the control line 108.

[0099] At the end of a work process, the relief valve 400 opens a bypass, which must be closed again so that compressed air can flow to the piston control via the main valve 100.

[0100] The main valve 100 allows compressed air to flow to the piston control 500 via line 109 in order to carry out a work process.

[0101] Furthermore, a shut-off valve 103, which is part of the main valve 100, is coupled to the pilot control valve 200 via the control line 107.

[0102] In the operating state shown here, the pilot control valve 200 is open and compressed air is constantly flowing out of the pilot control valve 200.

[0103] When the maximum pressure is reached, the pilot control valve 200 closes, so that pressure builds up in the control line 107, which activates the shut-off valve 103, so that the compressed air supply via the line 109 to the piston control 500 is interrupted.

[0104] Fig. 5 is a cross-section of the piston control 500. The piston control 500 comprises a plate arranged between the working chambers of the two pistons. In this exemplary embodiment, the line 109 is partially formed as a central channel leading to the working chamber 503 of a slide 504. The line 109 runs past the connecting channel 43 of the two pistons.

[0105] The control valves 50a and 50b move the slide 504 alternately to the left and right, via which compressed air is alternately fed to the left and right into the working chamber 503 of the slide 504.

[0106] The slide 504 comprises sections 504a, which open or close the respective exhaust air duct. These sections could be circular-cylindrical in shape.

[0107] Sections 504b serve to open or close the channel leading to the working chamber of a piston. Sections 504b can be dumbbell-shaped. Thus, a gate 504b can be surrounded by air, but is sealed at the edges from the working chamber 503 of the slide 504.

[0108] Fig. 6 is a central longitudinal section in the area of ​​the slide 504.

[0109] The housing of the piston control 500 includes the channel 505a, which leads into the working chamber 41a of the piston 42a, and the channel 505b, which leads into the working chamber of the piston 42b. Compressed air is alternately fed into one of the working chambers 41a, 41b via the slide 504.

[0110] Fig. 7 is a longitudinal section in the area of ​​the control valves.

[0111] The control valves 50a, 50b are alternately actuated by the pistons 42a, 42b, in that the piston 42a, 42b each strikes a tappet 51 of the control valve 50a, 50b.

[0112] In this illustration, the pistons 42a, 42b are just at the end of a reset process.

[0113] The control valve 50a is actuated. However, in this CAD representation, the plunger 51 overlaps with the piston 42b and is incorrectly depicted in the closed position.

[0114] Fig. 8 is a central longitudinal section of the tandem piston 40.

[0115] The tandem piston includes the connecting channel 43, via which the working chambers of the pistons are connected to each other.

[0116] Air can flow into the connecting channel 43 via an inlet 44, which may, for example, comprise several bores, and flow into the working chamber of the piston 42 at the outlet 45. During a working process, both pistons 42a, 42b are thus moved in the same direction.

[0117] Referring to Fig. 9 and Fig. 10, the piston control will be explained in more detail using a schematic representation.

[0118] In this illustration, pistons 42a, 42b are shortly before the end of a reset stroke. The slide 504 is in a position in which compressed air is only directed into the working chamber 41a. This resets the piston 42a and thus also the piston 42b.

[0119] As soon as the piston 42b presses on the tappet 51, the control valve 50b opens and the slide 500b moves in the direction indicated by an arrow.

[0120] Fig. 10 now shows how the slide 504 is moved into the position in which compressed air now flows into the working chamber 41b of the piston 42b.

[0121] In this working stroke, compressed air can flow from the working chamber 41b via the inlet 44 through the connecting channel 43 and flow via an outlet into the working chamber 41a of the piston 42a.

[0122] During one working cycle, both working chambers 41a, 41b are therefore supplied with compressed air.

[0123] Shown here is the position of pistons 42a, 42b shortly before the end of a work cycle. Piston 42a is located in front of plunger 51 of control valve 50a. If piston 42 moves further forward, control valve 52a opens, and slide 504 moves back to the position shown in Fig. 9 under compressed air control to initiate a reset cycle.

[0124] Fig. 11 is a further cross-section in the area of ​​the slide 504. The channel 506b for the exhaust air leading from the first working chamber is closed by the section 504a of the slide 504.

[0125] If the slide 504 is moved into the right position in this illustration via a control valve, the channel 506b is opened and the channel 506a is closed by the second working chamber.

[0126] The exhaust air is discharged via ducts in the housing, preferably via an expansion silencer.

[0127] Fig. 12 is an equivalent circuit diagram of the piston control system. The central compressed air supply is looped through to the directional control valve or spool 504.

[0128] Compressed air is alternately fed into the front and rear working chambers via the directional control valve, while at the same time the working chamber is opened and closed in the reverse order.

[0129] The control valves 50a, 50b are designed as 3 / 2-way valves and serve to switch the slide 504. Whenever a piston 42a, 42b contacts a control valve 50a, 50a, compressed air is fed into the working chamber of the slide (503 in Fig. 5). This compressed air is introduced in such a way that the slide 504 switches, i.e., moves to the right or left. Fig. 13 schematically shows the relationship between the volume flow q and the pneumatic pressure p in the pneumatic area, as it exists in a pressure generator according to the aforementioned prior art.

[0130] In an upstream regulator, the flow rate q decreases with increasing pressure p in the pneumatic system. It should be understood that this decrease does not necessarily occur linearly as shown here.

[0131] The area below the curve represents the hydraulic power during a work cycle. However, as shown in Fig. 14, the volume flow q theoretically does not change according to the invention until the maximum pressure is reached.

[0132] Rather, the volume flow q is set to zero via the pilot control valve when a maximum pressure is reached.

[0133] It has been shown that the hydraulic power could be approximately doubled in this way. Fig. 15 is a longitudinal section of an exemplary tool application 60. In this embodiment, the tool application 60 is designed as a blind rivet adapter. The tool application 60 includes a quick-release coupling 61, via which it can be coupled to the pressure generator.

[0134] In this embodiment, the tool application 60 comprises a pulling device 62 for pulling blind rivets.

[0135] However, the pressure generator according to the invention can also be coupled with other tool applications, for example, riveting clamps, spreading and crimping devices, etc. Due to the high hydraulic performance, it is also conceivable to use the pressure intensifier for hydroforming, for example.

[0136] List of reference symbols

[0137] 1 pressure intensifier

[0138] 2 housings

[0139] 3 Pneumatic connection

[0140] 10 handle

[0141] 11 triggers

[0142] 12 rods

[0143] 20 quick coupling

[0144] 21 Locking ring

[0145] 22 bullets

[0146] 23 Cage

[0147] 24 self-closing valve

[0148] 30 membrane

[0149] 40 tandem pistons

[0150] 41a Workroom

[0151] 41b Workroom

[0152] 42a piston

[0153] 42b piston

[0154] 43 connecting channel

[0155] 44 Entrance

[0156] 45 Exit

[0157] 50a control valve

[0158] 50b control valve

[0159] 51 plungers

[0160] 60 tool application

[0161] 61 quick coupling

[0162] 62 Towing device

[0163] 100 main valve

[0164] 101 pen

[0165] 102 valve body

[0166] 103 Shut-off valve

[0167] 104 Exit

[0168] 105 Entrance

[0169] 106 Control line (rapid feed) 107 Control line (pilot control valve)

[0170] 108 Control line (relief valve)

[0171] 109 Line (for piston control)

[0172] 200 Pilot control valve including control

[0173] 201 actuator

[0174] 202 pen

[0175] 203 Base / Pneumatic Valve

[0176] 204 spring

[0177] 300 hydraulic pump

[0178] 301 hydraulic piston

[0179] 302 pressure valve

[0180] 303 Suction valve

[0181] 304 lid

[0182] 305 Hydraulic line

[0183] 306 Membran

[0184] 400 relief valve

[0185] 401 valve body

[0186] 402 spring

[0187] 403 levers

[0188] 404 pistons

[0189] 500 piston control

[0190] 503 Working space (slide valve)

[0191] 504 slider

[0192] 504a Section (open / close exhaust air)

[0193] 504b Section (open / close compressed air)

[0194] 505a Channel to the first working chamber (compressed air)

[0195] 505b Channel to the second working chamber (compressed air)

[0196] 506a Duct from the first workroom (exhaust air)

[0197] 506b Duct from the second workroom (exhaust air)

Claims

Claims:

1. Pneumohydraulic pressure intensifier (1), comprising at least one Pneumatic piston (42a, 42b) coupled to a hydraulic pump (300), wherein the pressure intensifier (1) comprises a regulator via which the hydraulic output pressure can be adjusted, characterized in that the regulator is coupled to a hydraulic pilot control valve (200) via which the air supply to the pneumatic piston (42a, 42b) is interrupted when a set maximum pressure is reached.

2. Pneumohydraulic pressure intensifier (1) according to the preceding claim, characterized in that the hydraulic pilot control valve (200) is coupled to a pneumatic valve (203) which opens or closes a pneumatic control line (107) leading to a main valve (100).

3. Pneumohydraulic pressure intensifier (1) according to the preceding claim, characterized in that the main valve (100) is designed as a 5 / 2 or 5 / 3 way valve.

4. Pneumohydraulic pressure intensifier (1), in particular according to one of the preceding Claims, comprising at least one pneumatic piston (42a, 42b) which is coupled to a hydraulic pump (300) which delivers hydraulic fluid when the pneumatic piston (42a, 42b) is advanced, wherein the pneumatic piston (42a, 42b) can be reset by means of pneumatic pressure via a control valve (504).

5. Pneumohydraulic pressure intensifier (1) according to the preceding claim, characterized in that the pressure intensifier (1) comprises a tandem piston (40) with a first (42a) and a second piston (42b), wherein in a working stroke the first and second pistons (42a, 42b) are advanced by introducing compressed air.

6. Pneumohydraulic pressure intensifier (1) according to the preceding claim, characterized in that the compressed air is guided into the working chamber (41b) of the second piston (42b) and through a channel (43) connecting the first (42a) and second piston (42b) interconnects. Neumohydraulic pressure intensifier (1) according to one of the two preceding Claims, characterized in that the tandem piston (40) can be reset by introducing compressed air into the working chamber (41a) of the first piston (42a). Neumohydraulic pressure booster (1) according to one of the three preceding Claims, characterized in that a pneumatic control module is arranged between the working chamber (41a) of the first piston (42b) and the working chamber (41b) of the second piston (42b). Pneumohydraulic pressure intensifier (1) according to the preceding claim, characterized in that the control module comprises a control valve (50a, 50b) leading a piston (42a, 42b) into the working chamber (41a, 41b). Pneumohydraulic pressure intensifier (1) according to the preceding claim, characterized in that a directional control valve, which directs compressed air either to the working chamber (41a) of the first piston (42a) or to the working chamber (41b) of the second piston (42b), in particular a 5 / 2-way valve, in particular designed as a slide valve (504), can be actuated via the control valves (50a, 50b). Pneumohydraulic pressure intensifier (1) according to one of the preceding claims, characterized in that the pressure intensifier (1) is designed as a portable hand-held device.Pressing or drawing tool, in particular riveting, punching, crimping, spreading or cutting tool, comprising a pressure intensifier (1) according to one of the preceding claims.

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