1. Field of the Invention
This invention relates to an electrically operated pressing tool with a hydraulic pump which acts on a hydraulic piston-cylinder unit actively connected to a roller holder with rollers that roll on the clamping jaws of a clamping pincer and thus move these relative to one another. The pressing tool apparatus has a hydraulic oil accommodation container, as well as an actuation valve for opening a passage of a forward conduit into a return conduit between the hydraulic oil receiver container and the cylinder space of the piston cylinder unit.
2. Discussion of Related Art
Electrically operated pressing tools have been available on the market for many years. Portable, hydraulically impinged pressing tool apparatus of the initially mentioned type are used for pressing coupling elements, such as press sleeves, press fittings, pipe muffs, tube sections inserted into one another, and likewise. The pressing tools comprise a clamping pincer with clamping jaws, which form a pressing space for accommodating the coupling element to be pressed. The pressing force required for the pressing is generally provided by a hydraulic drive. All apparatus available today are relatively large and accordingly heavy. Reductions of the construction size have not been successful because of the demands which compellingly result from the construction shape, up to now. Changes in the size of the pressing pincers would limit their field of application and thus according to the knowledge present to this day, the pressing pincer may not be reduced in size. The corresponding roller holder must be adapted in size to the pressing pincer and this also applies to the fork-like receiver in which the pressing pincer is held and which is usually manufactured with the subsequent cylinder housing as one piece. The size of the cylinder housing is practically dependent on the forces to be mustered and these forces depend on the size of the clamping pincer. A conduit block arranged after the cylinder housing but manufactured with this as one piece creates the connections between the cylinder space and a subsequent hydraulic pump. Finally an electrometric drive, or a battery, for feeding the electric motor, yet follows the hydraulic pump.
The required hydraulic oil is suctioned out of a hydraulic oil container and is pumped into the cylinder. Thus, the piston is displaced in the actuation direction and the clamping pincer is closed. Once such a clamping procedure has been completed, then with many apparatus the hydraulic oil is pumped back into the hydraulic container and with some devices of this type, by way of a suitable actuation valve, a direct return from the forward conduit to a return conduit or suction conduit is effected. The mentioned functions necessitate a construction as described above. Accordingly, a miniaturization is practically not possible without a reduction in performance. A reduction in the size of the pressing pincer apparatus as a result may only be achieved by way of innovative measures.
Thus, it is one object of this invention to provide a pressing pincer apparatus of the initially mentioned type so that the overall construction of the apparatus may be reduced. A pressing pincer apparatus of the initially mentioned type, with the features of this invention, achieves this object. Thus, the volume of the apparatus is reduced by the space of a separately incorporated hydraulic oil supply container and the total apparatus and its housing is accordingly reduced.
The solution according to this invention may also be achieved with a pressing pincer apparatus having a manually actuatable actuation valve for returning the hydraulic oil from the forward conduit directly into the oil supply space via the return conduit. For this purpose, according to this invention, the actuation valve is attached so that in the piston-cylinder unit, it is completely covered by the elastic sleeve and the actuation of the valve is effected by pressure on the elastic sleeve. With this arrangement, the piston-cylinder unit may be constructed much shorter than previously possible.
Further advantageous embodiments of the subject-matter of this invention are discussed in this specification and in the claims, and their significance and manner of operation are explained in view of the accompanying drawings.
One embodiment of this invention is shown and described in more detail in the drawings, wherein:
One embodiment of the press tool apparatus according to this invention is shown in a form as will come onto the market. The actual function part is packaged in a plastic housing. The clamping pincer 2 which has two clamping jaws 5 held in a fork-like receiver via a secured bolt. The rollers 8 are located in the fork-like receiver and are rotatably mounted in a roller holder 7. The rollers 8 are pushed to the front by a piston cylinder unit, wherein the clamping jaws 5 close. In
For an improved understanding, the function part of a conventional pressing tool apparatus is known from European Patent EP-A-1,157,786, and is shown with reference to
After completion of the pressing procedure, the drive motor 14 is still and the hydraulic pump 3 is no longer in operation. By actuating the actuation valve 9, a connection is created between the forward conduit 10 and the return conduit 11 and the hydraulic oil flows into the cylinder space 12 back into the elastic hydraulic oil accommodation container 6. During this phase the restoring spring 16 pushes the piston 15 back into the initial position and the hydraulic oil flows through the described path via the actuation valve 9 into the elastic hydraulic oil accommodation container 6. With this design, the hydraulic oil accommodation container 6 lies below the piston cylinder unit 4 within a housing 0 of the pressing tool apparatus 1. This arrangement enlarges the overall housing 0 and thus the entire pressing tool apparatus 1. The solution according to this invention provides for a much more space-saving variation, which is simplified with regard to manufacturing technology.
Again the function unit as is shown in
A union nut 30 is pushed over the bearing head 24 and the hydraulic pump 3 and is screwed on the piston cylinder unit 4.
The piston cylinder unit 4 has a maximum diameter directly connecting to the union nut 30 and roughly corresponds to its diameter. In this region, the piston cylinder unit 4 comprises a first retaining groove 31. Subsequently, the piston cylinder unit 4 is reduced in diameter and thus forms an annular chamber 32. The volume of the annular chamber 32 is also enlarged by an annular groove 33. In the region of or near the cylinder housing 13, connecting to the annular chamber 32, an annular bead 34 is integrally formed on the cylinder housing, wherein the diameter of the annular bead 34 again corresponds to the diameter of the piston cylinder unit in the region of the first retaining groove. A second retaining groove 35 is formed into the annular bead 34. A sleeve 36, preferably of rubber-elastic material, covers the entire region between the first and the second retaining groove 31, 35. The elastic sleeve 36 thus forms the hydraulic oil accommodation container 6. The elastic sleeve 36 is held on the piston cylinder unit with a positive as well as a friction fit. For this, the elastic sleeve 36 comprises suitable beads which lie in the first and second retaining groove 31, 35. Clamping clips 37 arranged above and which may be cable binders ensure the non-positive connection. The piston-cylinder unit 4 is traversed by the actuation valve 9 within the region which is covered by the elastic sleeve 36 and preferably in the region in which the annular groove 33 is arranged for the increase of the volume. This actuation valve 9 lies perpendicularly with respect to the section plane in
The same actuation valve as in
Simultaneously, a filter 43 is applied between the actuation valve 9 and the bearing journal 41. The filter 43 may for example be realized of a sintered metal or plastic granulate with a suitably selected pore size. The oil filter 43 is passed through by the actuation plunger 49 and is accordingly sealed to the outside by a sealing ring 45.
The two
Number | Date | Country | Kind |
---|---|---|---|
2068/03 | Dec 2003 | CH | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/CH04/00620 | 10/12/2004 | WO | 4/12/2007 |