Abstract:
A hydraulic tool has a motor, a valve, a hydraulic intensifier, and a supply connector. The hydraulic intensifier is arranged between the valve and the motor. The valve and the motor are arranged behind one another in a longitudinal direction of the tool. The hydraulic intensifier has at least one intensifier piston having a movement direction that is positioned at a first angle greater than 0° relative to the longitudinal direction of the tool.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a hydraulic tool comprising a motor, a valve, a hydraulic intensifier, and a supply connector. 
   2. Description of the Related Art 
   The invention concerns in particular a transportable hydraulic rescue tool. Such a rescue tool can be configured as a hydraulic cutting device, a hydraulic spreader, a combination device, a cutter for pedals, a lifting device or a similar device. For example, a cutting device that is configured as hydraulic shears is required in order to be able to free in an automobile accident passengers of a greatly deformed motor vehicle. 
   Conventionally, such tools are supplied by a pressure source that is transported on a vehicle. Such a pressure source has a limited output pressure. In order to be able to provide the desired performance despite of this, the tools must be relatively large and heavy; this complicates their handling. 
   It has therefore already been suggested to provide such a tool with a hydraulic intensifier. In this case, the conduits that extend from the pressure source to the tool must have only a limited pressure resistance. The higher operating pressure is generated by the hydraulic intensifier directly within the tool. 
   However, this configuration requires also a certain size and stability because the valve must control the higher pressure. 
   SUMMARY OF THE INVENTION 
   It is an object of the present invention to design a transportable hydraulic tool such that it can be handled easily. 
   In accordance with the present invention, this is achieved in that the hydraulic intensifier is arranged between the valve and the motor. 
   Such a configuration provides the advantage that the motor of the tool can be operated at a relatively high hydraulic pressure. This pressure is provided by the hydraulic intensifier. However, it is not necessary to accept the disadvantage of having to configure the valve for a higher hydraulic pressure. The valve must only be able to withstand the pressure that is provided by the pressure source and is transmitted by the supply connector to the tool. Even though the valve must enable a higher throughput of hydraulic liquid, this is possible without problems in most cases. As mentioned before, the valve must be able to withstand only minimal pressures so that it can be of a small size and has only a minimal weight. Moreover, the valve becomes significantly more cost efficient. Since the valve can be smaller, the tool as a whole is lighter and thus also easier to handle. For the configuration of the motor of the tool there are different possibilities. For example, it is possible to design the motor as a single-action or double-action piston-cylinder arrangement. It is also possible to configure the motor as a rotary motor, for example, as a gear motor or gerotor motor. It is not necessary to provide hose conduits with fittings for higher pressures. All of the aforementioned units valve, hydraulic intensifier, motor, and tool are combined to a compact unit. 
   Preferably, the valve and the motor are arranged behind one another in the longitudinal direction and the hydraulic intensifier has at least one intensifier piston whose movement direction is positioned at an angle greater than 0° relative to the longitudinal direction. In this case, a significantly shortened length of the hydraulic intensifier in the longitudinal direction results. The user can therefore keep the tool significantly closer to the actual working area. This provides for a more comfortable working position so that working with minimal fatigue is possible. 
   Preferably, the angle is within the range of 70° to 110°. The movement direction of the piston therefore is positioned at an angle of approximately 90° relative to the longitudinal direction. Accordingly, the lifting stroke of the intensifier piston of the hydraulic intensifier practically plays no role in regard to the length of the hydraulic intensifier. Only the diameter of the intensifier piston has a certain effect on the size of the hydraulic intensifier in the longitudinal direction. It is therefore possible to size the hydraulic intensifier exclusively with respect to the pressure to be achieved without having to particularly consider other constructive conditions. 
   Preferably, the hydraulic intensifier has at least one control valve with a valve slide whose movement direction is positioned at a predetermined angle relative to the longitudinal direction. In this connection, it is thus also provided that the valve slide of the control valve is not moved in the longitudinal direction so that the movement stroke of the-valve slide and its axial length has practically no effect in the axial direction with respect to the size of the hydraulic intensifier. 
   Preferably, the angle of the intensifier piston and the angle of the valve slide are identical. The piston and the valve slide are therefore arranged parallel to one another and move parallel to one another. This facilitates the manufacture. Bores for the piston and the valve slide are required in only one direction. 
   Preferably, the intensifier piston and the valve slide are arranged adjacent to one another in a direction that is perpendicular to the longitudinal direction and perpendicular to the movement direction. The term perpendicular is not to be understood in its precise mathematical sense. Deviations from a right angle are therefore absolutely permissible as long as the size of the hydraulic intensifier in the longitudinal direction is not significantly increased. Accordingly, the valve slide, and the intensifier piston are arranged adjacent to one another, i.e., the width of the hydraulic intensifier is utilized in order to house these two elements. In this way, the length of the hydraulic intensifier in the longitudinal direction is not enlarged. The movement direction of piston and valve slide extends again perpendicularly to the longitudinal direction and perpendicularly to the transverse direction so that in this way also the length of the hydraulic intensifier is not increased. 
   Preferably, an intake valve and an outlet valve are arranged in the longitudinal direction on opposed sides of the intensifier piston. The intake valve and the outlet valve require a certain size but this size is however present anyway because in the surroundings of the intensifier piston a certain wall thickness must be provided in order to be able to withstand the high pressures that are generated. 
   Preferably, the hydraulic intensifier has a housing that is divided perpendicularly to the movement direction of the intensifier piston into at least two housing parts wherein the housing parts are connected to one another by clamping elements and wherein the intensifier piston is positioned closer to one clamping element than its correlated valve slide. In this way, forces that are the result of the generated high pressures as the intensifier piston is moved are diverted directly into the clamping elements. The clamping elements can be, for example, a threaded bolt. In this way, it is ensured that the seal-tightness of the housing is ensured also along the dividing line. 
   Preferably, one housing part has a through bore that forms a cylinder in which a low-pressure part of the intensifier piston moves. This configuration facilitates the manufacture. 
   Preferably, the hydraulic intensifier has an intensifier path with its own intensifier piston for each working direction of the motor. This has the advantage that a directional reversal by a valve is no longer required in the high pressure area but instead the directional reversal can be limited exclusively to the low-pressure area. 
   Preferably, the two amplifier pistons are arranged adjacent to one another perpendicularly to the longitudinal direction. In this way, the two intensifier pistons do not occupy more space in the longitudinal direction than a single intensifier piston. 
   Preferably, parallel to each intensifier path a stop valve is provided that can be controlled by a pressure within the other intensifier path, respectively. This facilitates the flow control of hydraulic liquid in one or the other working direction when generating the high pressure. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
     In the drawing: 
       FIG. 1  is a schematic illustration of a portable hydraulic rescue tool; 
       FIG. 2  is a schematic illustration of a hydraulic circuit diagram; 
       FIG. 3  is a plan view onto a hydraulic intensifier; 
       FIG. 4  is a section view of a hydraulic intensifier taken along section line IV—IV of  FIG. 5 ; and 
       FIG. 5  is a section view along section line V—V of  FIG. 4 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   A portable hydraulic rescue tool  1  in the embodiment illustrated in  FIG. 1  is in the form of shears. The shears have two jaws  2 ,  3  that are movable toward one another and are operated by a motor  4 . As can be seen in  FIG. 2 , the motor  4  is a double-acting piston-cylinder device. 
   At the end of the motor  4  facing away from the jaws  2 ,  3 , a hydraulic intensifier  5  is arranged that is attached to the motor  4  in a way not disclosed in detail. At the end of the hydraulic intensifier  5  facing away from the motor  4 , a valve  6  is arranged that controls by means of a rotary grip  7  the direction of movement of the jaws  2 ,  3 . The valve  6  in turn has a supply connector arrangement with a pump connector P and a tank connector T. The pump connector P, as shown in  FIG. 2 , is connected to a pump  8 . The tank connector T is connected to a tank  9 . Pump  8  and tank  9  can be arranged on a self-propelled device carrier, for example, a fire department vehicle. From there, the connection to the valve  6  is provided by means of a schematically illustrated conduit  10  whose length can be several tens of meters. 
   The pump provides a relatively low initial pressure of, for example,  20  bar. With this initial pressure theoretically the actuation of the tool  1  is conceivable. In order to generate a sufficient force, the tool  1  however would have to be sized relatively large. This would make handling more difficult. 
   The high pressure required within the tool  1  is made available by the hydraulic intensifier  5 . The hydraulic liquid is controlled however on the low-pressure side by the valve  6 . The hydraulic intensifier  5  is arranged between the valve  6  and the motor  4 . 
   The hydraulic intensifier  5  has a first low-pressure connector NA and a second low-pressure connector NB. Moreover, the hydraulic intensifier  5  has a first high-pressure outlet HA and a second high-pressure outlet HB. The two high-pressure outlets HA, HB are connected to the motor  4  and supply hydraulic liquid to the motor  4  at a pressure of, for example, several hundred bar. 
   In order to achieve this pressure intensification, the hydraulic intensifier  5  has its own intensifier path  14 A,  14 B for each movement direction of the motor  4 , i.e., for each working chamber  11 ,  12  on opposed sides of a piston  13 . In each intensifier path  14 A,  14 B an intensifier  15 A,  15 B is provided. Each intensifier  15 A,  15 B is connected in series to a check valve  16 A,  16 B. The outlet of the intensifier  15 A that is connected to the check valve  16 A is connected by a second check valve  17 A to the low-pressure connector NA. An intensifier inlet  18 A of the intensifier  15  A is also connected to the first low-pressure connector NA. A low-pressure connector  19 A of the first intensifier  15 A is connected to the second low-pressure connector NB. 
   In the same way, the outlet of the intensifier  15 B is connected by a check valve  17 B to the second low-pressure connector NB. An intensifier inlet  18 B of the intensifier  15 B is connected to the second low-pressure connector NB. The low-pressure connector  19 B of the intensifier  15 B is connected to the first low-pressure connector NA. 
   Parallel to the intensifier paths  14 A,  14 B, there is a stop valve  20 A,  20 B that is connected to the low-pressure connector NA, NB, respectively, that in turn is connected to the intensifier inlet  18 A,  18 B of the intensifier  15  A,  15 B, respectively, but can be controlled by means of the other low-pressure connector NB, NA, respectively. 
   By means of the valve  6  it is now controlled whether one of the low-pressure connectors NA, NB, and if so which one, is supplied with pressure by the pump  8  through the pump connector P. When, for example, the valve  6  is actuated to assume the above illustrated position, hydraulic liquid flows at low pressure through the low-pressure connector NA into the intensifier  15 A, is intensified therein, and is then discharged through the check valve  16 A to the high-pressure connector HA. The intensifier  15 A takes in through the check valve  17 A liquid from the low-pressure connector NA. At the same time, the stop valve  20 B that is parallel to the other intensifier path  14 B is actuated so that the working chamber  11  is enlarged by the supplied hydraulic liquid and the working chamber  12  becomes smaller as the liquid is discharged through the stop valve  20 B. The piston  13  moves in this case from the top to the bottom (relative to the illustration of  FIG. 2 ). When the valve  6  has been moved into the position that is illustrated at the bottom, the other supply path  14 B is pressurized and the piston  13  is moved from the bottom to the top. 
     FIGS. 3 to 5  show an end view ( FIG. 3 ) and sections views of the hydraulic intensifier  5 . The hydraulic intensifier  5  has a housing that is comprised of three parts in the present illustration: the bottom part  21 , the central part  22 , and the top part  23 . The three parts are held together by screws  24 . As illustrated in  FIG. 3 , the two low-pressure connectors NA, NB are arranged at one end face (the right side in  FIG. 4 ). 
   The tool  1 , as can be seen in  FIG. 1 , has a predominant longitudinal direction  25  that is illustrated by a line. Each intensifier  15 A,  15 B has an intensifier piston  26 A,  26 B whose movement direction is perpendicular to the longitudinal direction  25 . In this way, it is possible to keep the hydraulic intensifier  5  relatively short in the longitudinal direction  25 . Compared to a configuration in which the intensifier pistons  26 A,  26 B extend parallel to this longitudinal direction  25 , the extension can be reduced to less than half said length. 
   The intensifier piston  26 A,  26 B are arranged in cylinders  27 A,  27 B that are formed as through bores within the central part  22 . This simplifies the manufacture. The bores  27 A,  27 B form low-pressure cylinders that are connectable by valves, to be explained infra, to the low-pressure connectors NA, NB. 
   Each intensifier piston  26 A,  26 B has a low-pressure piston  28  and a high-pressure piston  29  that are connected to one another by a connection  30 . The two intensifier pistons  26 A,  26 B are identical so that only one intensifier piston  26 B will be explained in the following. 
   The high-pressure cylinder  31  communicates through the check valve  16 B with the second high-pressure connector HB and through the check valve  17 B with the low-pressure connector NB. The check valve  17 B forms an intake valve and the check valve  16 B an outlet valve. Intake valve and outlet valve are arranged in the longitudinal direction  25  on opposed sides of the high-pressure piston  29 . In this area, the top part  23  of the housing has a relatively great wall thickness so that the two valves  16 B,  17 B can be arranged therein without having to enlarge the required mounting space. 
   The valves required for controlling the intensifier pistons  26 A,  26 B have valve slides  32 A,  32 B that are movable parallel to the intensifier pistons  26 A,  26 B. Relative to their movement direction and relative to the longitudinal direction  25 , they are arranged adjacent to one another, i.e., they are arranged perpendicularly and behind one another relative to the plane of illustration of  FIG. 4 . 
   In this way, it is ensured that the housing  21 – 23  of the hydraulic intensifier  5  can be practically configured as a relatively flat disk. This disk has an extension in the longitudinal direction  25  of approximately 50 mm; it does not contribute significantly to an extension of the length of the tool  1 . 
   As can be seen in particular in  FIG. 5 , the intensifier pistons  26 A,  26 B are closer to the bolts  24  than the corresponding valve slides  32 A,  32 B. This contributes to a better absorption of the high pressures that are generated in the high-pressure cylinders  31 . 
   The function of a single intensifier piston is known in general in the prior art. For example, the valve slides  32 A,  32 B, can be constructed and the intensifier  1 SA,  15 B can be operated as disclosed in DE 196 33 258 C1. 
   It can be seen that the control slides  32 A,  32 B have a smaller diameter than the low-pressure pistons  28  of the intensifier pistons  26 A,  26 B. Accordingly, when it is indicated that the intensifier pistons  26 A,  26 B and the valve slides  32 A,  32 B are arranged adjacent to one another, this does not mean that their central axes must be arranged within a single plane. Displacements are obviously permissible as long as it is ensured that with such displacements the axial length of the hydraulic intensifier  5  is not significantly enlarged. In particular, the goal should be in this connection that the valve slides  32 A,  32 B are arranged within the open space that is delimited by tangential planes at the low-pressure pistons  28  of the intensifier pistons  26 A,  26 B. 
   While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.