Abstract:
An electric tool for applying a pressing force has a tool housing and a drive arranged in the tool housing. The drive has an electric motor and a drive element configured to be driven by the electric motor. The drive element is located externally to the tool housing. A pressing unit is connected to the drive element remote from the tool housing and has two pressing parts. The drive element acts on at least one of the two pressing parts for moving the at least one pressing part relative to the other one of the two pressing parts. The drive element is preferably a hydraulically actuated piston, and the electric motor operates a pump element that supplies hydraulic medium to the piston.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a device for applying a pressing force, comprising a housing in which a drive is arranged that has a motor and a drive element driven by the motor, and further comprising a pressing unit with two pressing parts wherein at least one of the two pressing parts is moved relative to the other pressing part during the pressing action. 
     2. Description of the Related Art 
     It is, for example, known to connect pipes fixedly to one another by pressing them together. In this context, radial as well as axial pressing techniques are employed. According to the radial pressing technique, a press fitting with inner or outer positioned sealing ring is manually inserted into the pipe or placed onto the pipe. The press fitting is then radially pressed by means of a device in the form of pressing pliers. 
     According to the axial pressing technique it is known to employ a press fitting comprised of a support sleeve and a pressure sleeve. In order to connect pipes to one another, one pipe is first widened before the press fitting can be inserted into the widened pipe end. This additional widening process is complex and requires an additional working step. The pressing sleeve is pressed by means of the device axially against the stop on the fitting. In another axial pressing technique, a pressing ring and a squeeze ring are slipped over the pipe. A support sleeve (fitting) is inserted into the pipe and the pressing ring is pressed by means of the device axially across the squeeze ring until it reaches the stop on the support ring. In this technique a prior widening of the pipe is not needed. 
     Devices are known which have two arms projecting from the base member and having at their free ends each a pressing part. The free ends of the arms are connected to one another by a spindle which can be rotated by means of a ratchet spanner. In this context, one arm is pivoted relative to the other arm. Because of this pivot movement, one pressing part moves along a circular arc which may result in problems during the pressing action on a straight pipe. 
     Moreover, a manually operated pressing device is known which operates similar to a pair of pliers. It has actuating arms which during the axial pressing process are pivoted back an forth relative to one another wherein a chain or a ratchet moves one of the pressing parts in the direction toward the other pressing part. This device has large dimensions and its use is cumbersome. 
     Moreover, a device is known in which one pressing part is provided on a sliding sleeve which can be moved by a hydraulic medium on the pipe piece in the direction toward the other pressing part. From one end of the pipe piece a further pipe piece projects perpendicularly via which the hydraulic medium is supplied. A hydraulic hose is connected to the free end of this further pipe piece which is connected to a hydraulic device arranged in the room. A grip projects perpendicularly from this further pipe piece and the device is held by this grip. Due to the described configuration, the device can be carried only with difficulty because the grip is arranged at the one end and the pipe piece support for the pressing parts is arranged at the other end of the pipe. Accordingly, a considerable force expenditure is required in order to hold the device during the pressing process. 
     Further pressing devices are configured as sliding pliers in which the pressing parts also perform a pivot movement which results in problems for straight pipes. 
     It is also known to convert such a pivot movement by an additional lever mechanism into a straight movement of the pressing parts. However, the constructive expenditure of such a device is high. Especially, the weight of such a pressing device, because of the additional lever mechanism, is greatly increased so that the manipulation during the pressing process is made much more difficult. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to configure the device of the aforementioned kind such that it has a simple design and provides a simple manipulation while ensuring a flawless pressing result. 
     In accordance with the present invention, this is achieved in that the device is an electric tool and that first the drive element and then the pressing unit are connected to the tool housing of the electric tool in series. 
     The device according to the invention is embodied as an electric tool in which the housing, the drive element for at least one of the pressing parts, and the pressing unit are arranged in series to one another. This results in a constructively simple configuration. Because of the position of the individual. parts, the device according to the invention can be of a compact configuration. Moreover, with this configuration an optimal weight distribution of the device is provided so that it can be held effortlessly during the pressing action. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     In the drawing: 
     FIG. 1 is a side view of the device according to the invention for pressing workpieces; 
     FIG. 2 is a sectional view of the device according to the invention shown in FIG. 1; 
     FIG. 3 is an enlarged representation in section of the pressing parts of the device according to FIG. 1 that are movable relative to one another; 
     FIG. 4 is a view in the direction of arrow IV of FIG. 3; 
     FIG. 5 is a sectional view of a portion of a second embodiment of the device according to the invention for pressing work pieces; 
     FIG. 6 is a sectional view of a part of a third embodiment of the device according to the invention for pressing work pieces; 
     FIG. 7 is an enlarged representation, rotated 90° relative to the illustration of FIG. 6, of the pressing unit of the device according to FIG. 6; and 
     FIG. 8 is an end view of the widening device of the device according to FIG.  6 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The device disclosed in the following in detail is used primarily in sanitary engineering for connecting pipes, pipe pieces etc. to one another in a non-detachable way. This includes a plastic deformation process which provides the fixed connection. Depending on the configuration of the device a radial or an axial pressing technique is used. According to the radial pressing technique pipes, pipe pieces, fittings etc. are inserted into one another and a radial pressing is performed by the device in the area of insertion. According to the axial pressing technique, the device axially moves a pressing ring onto the pipe, pipe piece, fitting so that by means of the pressing ring a radial plastic deformation takes place. 
     In the embodiment according to FIGS. 1 through 4, the device is a portable tool which can be carried comfortably by the operator. The device has a tool housing  1  which is advantageously comprised of two detachably connected housing parts. Of course, the tool housing  1  can also be comprised of more than two housing parts. The tool housing  1  is pistol-shaped and has an elongate housing part  2  in which a hydraulic part  3  (FIG. 2) of a drive  4  is arranged. Below the housing parts  2  a housing part  5 , that is longer in the axial direction, is positioned in which a mechanical part  6  of the drive  4  is arranged. A grip  7  projects transversely from the housing part  5  which is also a portion of the tool housing  1  and in which an electric/electronic part  8  of the drive  4  is positioned. The grip  7  is recessed relative to the housing part  5 . The longitudinal axis  9  of the grip  7  is positioned at an obtuse angle α relative to the longitudinal axis  10  of the housing part  5 . The longitudinal axis  10 , in turn, is positioned parallel to the longitudinal axis  11  of the housing part  2  (FIG.  1 ). In front of the grip  7  a hollow stay  12  is provided which extends approximately parallel to the longitudinal axis  9  of the grip  7  and is spaced from it. This creates the grip opening  13  between the grip  7  and the stay  12 . The stay  12  and the grip  7  are connected to one another by an integral transverse piece  14  which is also formed as a hollow part. 
     During the pressing action, the device is preferably held by the grip  7 , wherein the operator grips the grip  7 , as indicated in FIG. 2 by dash circles. The hand of the user extends thus through the grip opening  13 . The stay  12  protects the hand of the user during the pressing process. At the transition of the grip  7  to the housing part  5  a switch  15  projects from the grip  7  into the grip opening  13 . When gripping the grip  7 , the switch  15  can be easily squeezed by the index finger in order to turn on the drive  4 . The switch  15  can be configured such that it must be constantly squeezed during the pressing action. As soon as the switch  15  is released, the drive  4  is turned off. However, it is also possible to configure the switch  15  such that it is only squeezed once for turning on the drive  4  and then squeezed a second time for turning off the drive  4 . This latter embodiment has the advantage that the operator must not squeeze the switch  15  during the entire time of the pressing process. In this case, the device can also be gripped such that the hand grips the grip  7  and the stay  12 , as indicated in FIG. 2 by further dash circles. In order to provide in this scenario a safe grip for the hand, the housing part  5  as well as a portion of the stay  12  at a side facing a way from the grip  7  are provided with grip depressions  16  so that the fingers can securely hold onto the tool housing  1 . 
     The transverse piece  14  of the tool housing  1  can be a receptacle for at least one accumulator or a battery. The device can also be operated by current supplied from the mains supply. In this case, an electric cable (not shown) extends from the tool housing  1 , preferably downwardly from the transverse piece  14 . 
     The electric/electronic part  8  of the drive  4  is arranged within the narrow grip  7  to thereby save space. The electric/electronic part  8  switches on and off the mechanical drive part  6 . This drive part  6  comprises an electric motor  17  whose axis  18  extends parallel to the longitudinal axis  10  and advantageously coincides with this longitudinal axis. The motor shaft  20  projecting from the motor housing  19  is coupled to the reducing gear unit  21  arranged downstream which is advantageously configured as a planetary gear unit. The reducing gear unit  21  is advantageously at least of a two-step design. The preferred use of a planetary gear unit as the reducing gear unit  21  has the advantage that only minimal space is required while a high reducing gear ratio is provided. Accordingly, the reducing gear unit  21  can be arranged in a space saving way within the housing part  5 . The longitudinal axis  22  of the reducing gear unit  21  is advantageously arranged so as to be aligned with the longitudinal axis  18  of the motor  17 . 
     The drive shaft  23  of the reducing gear unit  21  supports an eccentric piece  24  external to the housing  25  of the reducing gear unit  21 . An elliptical ring  26  is positioned with or without interposition of an intermediate ring on the eccentric piece  24 . The longer axis of this elliptical ring  26  extends transversely to the axis of the drive shaft  23 , i.e., transversely to the plane of the drawing, while the smaller axis is positioned with in the plane of the drawing according to FIG.  2 . The eccentric piece  24 , or the round intermediate ring seated on it, rests against the inner wall of the portions of the ring  26  extending perpendicularly to the plane of the drawing. When the drive shaft  23  is rotated about its axis, the ring  26  is moved up and down by means of the eccentric piece  24  in the direction of the double arrow  27  in FIG. 2 within the plane of the drawing. Such an eccentric drive is known and is therefore not explained in detail in this context. 
     The elliptical ring  26  supports a piston  28  which is preferably a unitary part of the ring  26  but can also be fixedly connected thereto. The piston  28  projects with play all around from the housing  30 , which receives the eccentric drive  23 ,  24 ,  26 , into a piston chamber  31  which is advantageously formed by a bore in a hydraulic unit  32 . It is arranged in the housing part  2  of the tool housing  1  and supported on the housing  30  of the eccentric drive  23 ,  24 ,  26  and fastened thereto. At one end of the hydraulic unit  32 , a reservoir  33  for a hydraulic medium, preferably a hydraulic oil, is provided. A closable filling opening  35  is provided on the bottom  34  of the hydraulic medium reservoir  33  positioned opposite the hydraulic unit  32  via which hydraulic medium can be filled into the hydraulic medium reservoir  33 . A check valve  36  projects into the hydraulic medium reservoir  33  which closes a bore  37 , extending transversely to the piston chamber  31 , relative to the hydraulic medium reservoir  33 . The bore  37  having a smaller flow cross-section then the piston  31  opens into the piston chamber  31  at the chamber end remote from the eccentric drive  23 ,  24 ,  26 . In this area a supply bore  38  opens also into the piston chamber  31 . This bore  38  is also provided within the hydraulic unit  32  and extends transversely to the piston chamber  31  and is advantageously aligned with the bore  37 . The supply bore  38  supplies the hydraulic medium for actuating a pressing part  39 , and this which will be explained in more detail in the following. 
     The longitudinal axis  85  of the hydraulic unit  32  is advantageously positioned so as to coincide with the longitudinal axis  11  of the housing part  2 . The two bores  37 ,  38  in the hydraulic unit  32  are positioned advantageously on the side of the longitudinal axis  85  of the hydraulic unit  32  facing away from the reducing gear unit  21 . The piston chamber  31  is positioned in the shown embodiment in a transverse center plane  29  of the hydraulic unit  32 . The piston  28  is guided in a sealed way within the piston chamber  31  and serves to take in hydraulic medium from the hydraulic medium reservoir  33  and to supply it through the supply bore  38  to the pressing unit  40  by means of its reciprocating movement. 
     The hydraulic unit  32 , as illustrated in FIG. 3, has a recess  41  at its end facing away from the hydraulic medium reservoir  33  into which a projection  42  of the pressing unit  40  is inserted. The pressing unit  40  is detachably fastened by securing screws  43  in the recess  41  of the hydraulic unit  32 . The projection  42  is penetrated axially by a bore  44  which is in flow connection with the supply bore  38  of the hydraulic unit  32  via an annular groove  87  when the pressing unit  40  is mounted. The projection  42  is sealed by at least one annular seal  45  relative to the inner wall of the recess  41  of the hydraulic unit  32  so that the hydraulic medium cannot exit to the exterior from the recess  41  of the hydraulic unit  32 . 
     The projection  42  projects centrally from a bottom  46  of the pressing unit  40 . The bottom  46  is plate-shaped and extends in a plane that is transversely to the longitudinal axis  85  of the hydraulic unit  32 . The end of the bottom  46  facing away from the grip  7  and the stay  12  is connected to a wall  47  projecting transversely thereto, wherein the bottom  46  and the wall  47  are preferably formed as a monolithic part. The wall  47  connects the bottom  46  with a wall  48  which extends parallel to the bottom  46  and which is advantageously also formed as a unitary (monolithic) part of the wall  47 . The bottom  46  and the two walls  47 ,  48  are closed at their ends positioned above and below the plane of the drawing according to FIG. 3 by further walls. All walls form a monolithic part and delimit a centrally positioned cylinder chamber  49  (FIGS. 3 and 4) into which a drive element in the form of a piston  50  can be inserted in a seal-tight way. The bottom  46 , the walls  47 ,  48  as well as the further walls connecting them thus form a drive element housing (piston housing)  51  in which a cylinder chamber  49  is defined. The drive element housing  51  has a rectangular, in particular, square contour, as can be seen in FIG. 4 when viewed in the direction of the axis  52  of the piston  50 . The drive element housing  51  supports on the side facing away from the tool housing  1  a stationary pressing part  53  positioned opposite the other pressing part  39 . The two pressing parts  39 ,  53  are identical but mirror-symmetrically arranged to one another. Accordingly, in the following only the pressing part  39  will be explained in more detail with the aid of FIG.  4 . 
     The pressing part  39  is bracket-shaped and has an approximately half-cylindrical receptacle  54  for the workpiece to be pressed. The receptacle  54  is delimited, in a view according to FIG. 4, by an approximately semi-circular bracket  55  from which project two parallel legs  56 ,  57  which are connected to one another by a transverse bolt  58 . 
     The two legs  56 ,  57  are connected by the transverse bolt  58  to a slide  59  which is U-shaped in the plan view according to FIG.  4 . The slide  59  rests with flat legs  60 ,  61  against the parallel outer sides  62 ,  63  of the drive element housing  51  in areal engagement. The outer sides  62 ,  63  are provided with an outwardly oriented projection  64 ,  65  having coordinated therewith corresponding projections  66 ,  67  at the inner sides of the legs  60 ,  61  of the slide  59 . The projections  64 ,  65 ;  66 ,  67  extend across the length of the outer sides  62 ,  63  and of the legs  60 ,  61 . The projections ensure that the slide  59  cannot be removed transversely to the projections from the drive element housing  51 . 
     The stay  68  of the slide  59  connecting the two legs  60 ,  61  rests against the wall  48  of the drive element housing  51 . At half the width of the stay  68 , the projection  69  extends away from the stay  68  at the side facing away from the housing  51  and engages between the two legs  56 ,  57  of the pressing part  39 . It is penetrated by the transverse bolt  58 . The legs  56 ,  57  rests against the outer sides of the projections  69 . Moreover, the end faces  70 ,  71  of the two legs  56 ,  57  rest against the stay  68  of the slide  59 . This prevents tilting or canting of the pressing part  39  relative to the slide  59 . 
     The two legs  60 ,  61  of the slide  59  extend approximately over the entire length of the drive element housing  51 . It is open at the side opposite the wall  47 . It is closed by a plate-shaped support  72  (FIG. 3) which connects the free ends of the legs  60 ,  61  and to which is fastened the piston  50 . The walls  46 ,  62 ,  63  of the drive element housing  51  delimit with their free ends a recess  73  which is engaged by the support  72  when the piston  50  is in the retracted position (FIG.  3 ). In this position, the support  72  contacts the bottom  74  of the recess  73 . The piston surface  75  positioned opposite thereto and loadable by the hydraulic medium has in this position still a spacing from the bottom  76  of the cylinder chamber  49 . This ensures that the hydraulic medium can still reach the piston surface  75  even when the piston  50  is completely retracted. 
     The projection  69  of the slide  59  extends, as is shown in FIG. 3, only over a portion of the height of the drive element housing  51 . FIG. 3 shows the initial position of the pressing part  39  in which it has the greatest spacing from the oppositely positioned pressing part  53 . In contrast to the pressing part  39 , the pressing part  53  is rigid and preferably formed as a unitary (monolithic) part of the drive element housing (piston housing)  51 . During the pressing action, the pressing part  39  is moved against the pressing part  53 . The slide  59  ensures a proper, especially canting-free, guiding of the pressing part  39  on the piston housing  51 . 
     The two brackets  55  of the pressing parts  39 ,  53  are provided at their sides facing away from one another with reinforcements  78 ,  79  which extend almost over the entire circumference of the brackets  55  and increase steadily from the bracket ends in the direction toward the projection  69 . Accordingly, the reinforcements  78 ,  79  have a triangular contour transverse to the direction of movement of the pressing part  39  (FIG.  3 ). Because of these reinforcements  78 ,  79  very high pressing forces can be applied without the risk of unacceptable deformation of the brackets  55  of the pressing parts  39 ,  53 . 
     In order to guide the hydraulic medium into the cylinder chamber  49 , the bore  44  (FIG. 3) extends into the wall  46  of the piston housing  51 . The end of the bore  44  positioned in this wall  46  is connected to a bore  80  which extends transversely thereto in the wall  46  and leads to the outer side of the wall  47  of the piston housing  51 . The bore  80  can thus be easily produced in this configuration in the piston housing  51 . The bore  80  is closed with respect to the outer side of the wall  47 . The connection of the bore  80  with the cylinder chamber  49  is realized by a further bore  81  which projects from the outer side of the wall  46  of the piston housing  51  into the cylinder chamber  49 . Accordingly, this bore  81  can also be produced with a simple manufacturing process. The bore  81 , which extends transversely to the bore  80 , is closed relative to the outer side of the housing wall  46 . 
     The pressing unit  40  can be rotated about the axis  82  of its projection  42 . For this purpose, the outer side of the cylindrical projection  42  is provided with an annular groove  83  which is engaged by securing screws  43 . This secures the pressing unit  40  against lifting off the tool housing  1  but allows a continuous rotation about the axis  82 . This has the advantage that the pressing parts  39 ,  53  can be rotated into the optimal position for the pressing action. 
     At the begin of the pressing action the pressing part  39  is advantageously in the initial position illustrated in FIGS. 2 and 3. The two brackets  55  of the pressing parts  39 ,  53  are positioned parallel to one another. An axial pressing technique is performed by the pressing unit  40 , such pressing technique being known in general. For example, a pressing ring and a squeeze ring are slipped onto a pipe into which a support sleeve has been inserted. The pressing ring is then pressed with the aid of the pressing unit  40  axially across the squeeze ring until it reaches the stop on the support sleeve (fitting). This axial movement of the pressing ring results in a radial pressing action. The pipe is inserted such into the two pressing parts  39 ,  53  that the pressing ring to be moved is arranged between the two pressing parts  39 ,  53  and rests with one end against the pressing part  39 . When the pressing part  39  is moved in the direction of the pressing part  53 , the forked bracket  55  of the pressing part  39  entrains the pressing ring and moves it across in the squeeze ring positioned on the pipe until the pressing ring contacts the support sleeve. The support sleeve then rests axially against the fork  55  of the pressing part  53 . 
     In order to move the pressing part  39 , the motor  17  is turned on by means of the switch  15 . The high rotational speed of the motor shaft  20  is reduced by the reducing gear unit  21  into a correspondingly low rotational speed of the drive shaft  23  of the reducing gear unit  21 . The eccentric piece  24  seated on the drive shaft  23  thus performs an eccentric movement. The elliptical ring  26  is reciprocated in the direction of arrow  27  (FIG. 2) so that the piston  28  in the piston chamber  31  of the hydraulic unit  32  is accordingly reciprocated also. When the piston  28  moves downwardly from the position illustrated in FIG. 2, it takes in hydraulic medium via the check valve  36  and the bore  37  from the hydraulic medium reservoir  33 . When the piston  28  is moved upwardly, the hydraulic medium, which is present in the bore  37  as well as in the piston chamber  31 , is pressurized and conveyed via the bores  38 ,  44 ,  80 ,  81  into the cylinder chamber  49 . The piston  50  is thus pressurized so that it is moved from the position according to FIGS. 2 and 3 in the downward direction. By means of the support  72  and the slide  59  connected thereto the pressing part  39  is moved in the direction of the oppositely positioned pressing part  53 . The fork  55  of the pressing part  39  entrains the pressing ring and moves it across the squeeze ring. The piston  28  in the hydraulic unit  32  is continuously reciprocated by the rotation of the eccentric piece  24  and, in the afore described manner, conveys the hydraulic medium into the cylinder chamber  49  and thus continuously moves the piston  50  positioned therein in the downward direction. As soon as the pressing ring contacts the support sleeve, the motor  17  is advantageously automatically turned off. The point in time for turning it off can be determined simply in that t the point of contact of the pressing ring on the support sleeve the pressure required for a further movement of the pressing part  39  increases suddenly so that this pressure increase is detected and used for turning off the motor  17 . At the same time, this pressure increase opens the pressure limit valve (not shown) so that the hydraulic medium can flow back from the piston chamber  49  by a return bore (not shown) to the hydraulic medium reservoir  33 . This return flow is initiated by the piston  50  being returned by a spring force into its initial position according to FIG.  3 . FIG. 4 shows two pressure springs S 1 , S 2  which are positioned partially in the drive element housing  51  and are supported on the legs  60 ,  61  of the slide  59 . The pipe can be removed easily in a direction transversely to the movement direction of the pressing part  39  from the pressing unit  40 . 
     The described device is very compact and also lightweight. The tool housing  1  with the drive  4  arranged therein, the piston  50  and the pressing part  39  are positioned in series when viewed in a direction transverse to the movement direction of the pressing part  39 . This results in a compact configuration and especially in an optimal weight distribution of the device. It is not top heavy so that it can be held by the user during the pressing action and also thereafter comfortably. The device ensures a simple manipulation and handling. 
     An important feature of this device is also to be seen in that the axis  82  of the projection  42  which is a coupling member of the pressing unit  40  extends through the range of maximum travel  84  (FIG. 3) of the pressing part  39 . The two pressing parts  39 ,  53  are thus positioned at least partially on either side of the axis  82  of the projection  42  which results in an excellent weight distribution. 
     The coupling member in the form of the projection  42  ensures an optimal connection to the hydraulic unit  32 , in particular, since the bore  44  is provided in the projection  42  which, after coupling, provides communication with the bore  38  provided in the hydraulic unit  32  via the annular groove  87 . Accordingly, no hoses or tubes are required as connecting pieces for conveying the hydraulic medium from the hydraulic medium reservoir  33  to the pressing unit  40 . Instead, the conveying of the hydraulic medium is realized exclusively via bores provided within the device so that the problem of leakage is at least reduced. Since the device has no external hoses etc., the pressing action is considerably simplified because the user must not pay attention to externally positioned connecting hoses. 
     The piston  50  is positioned transversely to the axis  82  of the projection  42 . This position results also in an excellent weight distribution which ensures an optimal handling of the device. 
     Since the pressing unit  40  can be rotated, it can be adapted on site by a corresponding rotational movement to the parts to be pressed. For example, it is thus possible to press with the pressing unit  40  also already mounted pipes wherein in such situations the pressing unit  40  can be easily adapted to the given position of the mounted pipes etc. 
     A further important feature of the device is to be seen in that the pressing unit  40  can be rotated about the axis  82  of the projection  42 . Advantageously, the axis  82  is positioned at least in approximation in a symmetry plane of the pressing unit  40 , relative to the initial position of the pressing part  39  illustrated in FIG.  3 . With this configuration the weight distribution upon rotation of the pressing unit  40  is not changed or changed only insignificantly. Accordingly, the device can be held optimally in any position of the pressing unit  40 . 
     The axis  82  of the projection  42  is positioned preferably so as to coincide with the axis  85  of the hydraulic unit  32  which coincides, in turn, advantageously with the longitudinal axis  11  of the housing part  2 . This also ensures an excellent weight distribution which results in a simple handling of the device during the pressing action. 
     FIG. 5 shows an embodiment in which the pressing parts of the pressing unit perform a radial pressing action. In this case, the two pressing parts  39 ,  53  of the pressing unit  40  are rotated by 90° relative to one another in comparison to the previous embodiment, so that the receptacles  54  of its two forks  55  are oriented against one another. FIG. 5 shows the end position of the pressing part  39  in which its fork rests at the fork  55  of the stationary pressing part  53 . The pressing part  39 , as in the previous embodiment, is fixedly connected to the slide of which only the support  72  is shown in FIG. 5 which supports the piston  50 . The device of this embodiment is otherwise identical to the previous embodiment. 
     For a radial pressing action, the receptacle  54  of the pressing part  53  receives the respective pipe or pipe piece. At the beginning of the pressing action, the piston  50  is retracted so that the pressing part  39  is positioned at a corresponding spacing to the pressing part  53 . As has been explained in detail with the previous embodiment, the piston  28  is continuously reciprocated in the hydraulic unit  32  thus conveys the hydraulic medium into the cylinder chamber  49  so that the piston  50  is moved downwardly in FIG.  5 . The pipe, pipe piece, support sleeve etc. in the receptacle  54  of the pressing part  53  is thus radially pressed. FIG. 5 shows the workpiece  86  radially pressed by the two pressing parts  39 ,  53 . 
     This embodiment also provides the same advantages as the previously described embodiment. 
     The two embodiments are each embodied as an electro-hydraulic tool wherein one pressing part  39  is moved by being loaded with hydraulic medium via the piston  50 . In a simpler embodiment (not shown) the movement of the pressing part  39  can also be mechanically achieved, for example, by a spindle drive. In this case, a hydraulic medium is not required. In this case, the motor  17  drives by means of the reducing gear unit  21  the spindle drive by which the pressing part  39  is then moved relative to the other pressing part  53 . 
     FIGS. 6 through 8 show a device which, in accordance with the previous embodiments, is also embodied as an electro-hydraulic portable tool. The two pressing parts  39 ,  53  of the pressing unit  40  are provided for realizing an axial pressing action. The drive of the pressing parts  39 ,  53  is realized in the same manner as in the embodiment according to FIGS. 1 through 4. The pressing unit  40  has the projection  42  which engages the recess  41  of the hydraulic unit  32 . In the housing  51  of the pressing unit  40  the piston  50  is reciprocatingly movable by means of a hydraulic medium, as has been disclosed in connection with the embodiment according to FIGS. 1 through 4. The pressing parts  39 ,  53  are secured exchangeably in corresponding receptacles  88 ,  89 , as in the previous embodiments. They have cylindrical receptacle chambers  90 ,  91  which receive cylindrical pins  92 ,  93  of the pressing parts  39 ,  53  in a positive-locking manner. The cylindrical pins  92 ,  93  are provided with annular grooves  94 ,  95  in a radial plane. The grooves  94 ,  95  are engaged by catch elements  96 ,  97 , preferably in the form of catch balls. They are loaded by coil springs  98 ,  99  which are secured in transverse bores  100 ,  101  of the receptacles  89 ,  88 . For securing the catch elements  96 ,  97  the transverse force  100 ,  101  are closed by locking screws  102 ,  103 . In the mounted position the pressing parts  39 ,  53  rest with a base member  104 ,  105  on the end faces  106 , 107  of the receptacles  88 ,  89 . 
     The pressing parts  39 ,  53  are advantageously of a monolithic configuration. Since the cylindrical pins  92 ,  93  of the pressing parts  39 ,  53  are cylinder-shaped, they can be manufactured in a simpler and less expensive manner in comparison to conventional pressing parts. In conventional pressing parts, the insertion projection is comprised of a rectangular projection part connected to the base member and a cylindrical projection part connected to the rectangular part. This results in a complicated and expensive manufacture of these pressing parts. The annular grooves  94 ,  95  can also be easily and inexpensively provided on the pins  92 ,  93 . Moreover, it is advantageous that the catch elements are positioned in the receptacles  88 ,  89  of the tool instead of on the pressing parts themselves, as is conventional in the prior art. Thus, only two catch elements  96 ,  97  are required in order to secure pressing parts  39 ,  53  of different configurations in the receptacles  88 ,  89 . Since the pressing parts  39 ,  53  have as an insertion projection only the pins  92 ,  93 , they can have a relatively large diameter so that also great forces can be received during the pressing action. 
     Advantageously, the receptacles  88 ,  89  are provided with supports  108 , 109  for the pressing parts  39 ,  53 . The supports  108 , 109  are provided such on the receptacles  88 ,  89  that the pressing parts  39 ,  53  are supported on these supports with respect to the reaction force occurring during the pressing action. This results in a favorable force transmission during the pressing action. The supports  108 ,  109  are advantageously ledge-shaped and project from the end faces  106 ,  107  of the receptacles  88 ,  89 . The pressing parts  39 ,  53  are positioned with their base members  104 , 105  on the supports  108 ,  109  which are advantageously formed as monolithic parts of the receptacles  88 ,  89 . 
     Depending on the size of the workpieces to be pressed, differently sized pressing parts  39 ,  53  can be inserted into the receptacles  88 ,  89 . The pins  92 ,  93  are relatively short so that the pressing parts  39 ,  53  have a compact configuration which also results in a favorable force introduction and force transmission. 
     The pins  92 ,  93  are positioned eccentrically relative to the base members  104 ,  105 . The spacing  110 ,  111  (FIG. 6) between the axis  112  of the pins  92 ,  93  and the oppositely positioned outer sides  113 ,  114  of the base members  104 ,  105  of the pressing parts  39 ,  53  are different. This has the advantage that the pressing parts  39 ,  53  cannot be inserted side-inverted into the receptacles  88 ,  89 . 
     The pressing parts  39 ,  53  are otherwise of identical configuration as in the embodiment according to FIGS. 1 through 4. The workpieces to be axially pressed relative to one another are inserted in the above disclosed manner into the pressing parts  39 ,  53 . Subsequently, by actuation of the switch  15  (FIGS. 1 and 2) the motor  17  (FIG. 2) is turned on so that the two pressing parts  39 ,  53  are moved relative to one another to perform the axial pressing action. As in the embodiment according to FIGS. 1 through 4, the axis  82  of the projection  42  extends through the range of maximum travel of the pressing part  39 . The two pressing parts  39 ,  53  are thus positioned at least partially on either side of the axis  82  of the projection  42  so that an optimal weight distribution results. 
     A pipe widening device  115  can be connected to the pressing unit  40 . It has a pipe widening housing  116  (FIG. 7) that is open on both ends and in which a widening mandrels  117  is arranged in a manner known in the art. The housing  116  has a radially outwardly oriented flange  118  at a side facing the pressing unit  40  via which the pipe widening device  115  can be detachably fastened to the pressing unit  40 . The axis of the pipe widening device  115  coincides with the axis of the piston  50 . 
     Onto the end of the housing  116  facing away from the pressing unit  40  a nut  119  can be screwed which contains widening segments  120 . As is illustrated in FIG. 8, six widening segments  120  are provided which in the retracted position of the widening mandrels  117  rest with their lateral surfaces against one another. The widening segments  120  engage with radially outwardly projecting stays  121  an annular chamber  122  which is provided on the inner side of the nut  119 . The annular chamber  122  is of such a radial width that the widening segments  120  during the widening process can be moved sufficiently far radially outwardly. The widening segments  120  are axially secured in the annular chamber  122 . 
     FIG. 7 shows the upper half of the widening mandrel  117  in a retracted position in which the widening segments  120  are resting against one another, as is known in the prior art. The lower half of FIG. 7 shows the widening mandrel  117  in the extended position. The widening segments  120  are radially moved outwardly when the widening mandrel is extended so that the pipe placed onto the widening segments  120  is radially widened. The widening segments  120  are provided at their inner side with a conical surface  123  with which the widening segments  120  rests against the conical widening mandrel  117 . At their outer side the widening segments  120  are provided, in a manner known in the art, with partial cylindrical surfaces  122  which during the widening process rests against the inner side of the pipe to be widened. 
     With this optional pipe widening device  115  it is thus possible to widen, if needed, pipes before the pressing action. For this purpose, the pipe is positioned with its one end on the widening segments  120 . Subsequently, by actuating the switch  15 , the motor  17  is turned on so that the piston  50  is moved in the manner described in connection with FIGS. 1 through 4. The bottom  76  of the piston  50  upon movement contacts the plate-shaped end piece  125  of the widening mandrel  117 . It is thus moved away from its initial position (upper half of FIG. 7) so that the widening segments  120  are radially outwardly moved and the pipe end is widened. As soon as the widening process is completed, the motors  17  is turned off. The piston  50  is then returned in the afore described manner by a spring force into its initial position. The widening mandrel  117  is also advantageously loaded by a spring force so that, upon return of the piston  50 , the widening mandrel  117  is also returned into its initial position. The widening segments  120  are also loaded by a spring force so that the widening segments  120  upon return of the widening mandrel  117  are radially retracted. 
     After the widening process, the pipe is removed and slipped onto a support sleeve of a fitting which is inserted into the corresponding pressing part  39  or  53 . The pressing sleeve to be pressed with the fitting and already pushed onto the pipe is inserted into the other pressing part. It is pressed axially by the pressing unit in the afore described manner onto the wide end supported on the support sleeve. 
     Depending on the inner diameter of the pipe to be widened, nuts  119  with corresponding widening segments  120  can be screwed onto the housing  116  of the pipe widening device  115 . Moreover, the user of the device, if the pipe widening device  115  is not needed, can remove it at any time from the pressing unit  40 . 
     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.