Metal deforming – With means to drive tool – Including link-actuated tool support
Patent
1994-07-11
1995-12-26
Jones, David
Metal deforming
With means to drive tool
Including link-actuated tool support
72456, B21J 1526, B21J 918
Patent
active
054777259
DESCRIPTION:
BRIEF SUMMARY
The object of the invention consists in the structural design of an articulated lever press which may be applied in the most versatile manner, in principle, in the field of non-cutting metal shaping.
This object is met by an articulated lever press with the features of the main claim. The subclaims contain preferred constructions and alternative solutions.
The articulated lever press, according to the invention, has a straight-sided or double-column type C-shaped frame, known per se. A base guiding body is arranged between the two column cheeks and forms a unit with the base of the press. However, there is not normally a connection between the guiding body, the column cheeks loaded by the pressing force, and the upper part of the press. If the column is shifted due to the pressing force and reaction forces, the guidance, which is separate from the column, remains unaffected.
The guide may be constructed as a wrap-around six-way flat guide in which each guideway guides the ram or slide in only one direction and is free in the other direction. Accordingly, e.g. in the event of heating and the enlargement resulting therefrom, the slide is always guided accurately without jamming.
The guideways for guiding the slide are so designed that the space above the press table is not limited by projecting guide parts. This is advantageous in that parts of the tool or die projecting beyond the surface of the slide do not restrict the lift or travel of the slide or substantially reduce the guideways so as to negatively affect the guidance characteristics. According to the invention, the slide is guided along the full height of the slide surface in every case.
Further, the slide guidance can also be continued below the slide surface.
The slide is driven by a combined articulated lever function and lever function, wherein these two functions can run consecutively with respect to time. During the closing movement, the articulated lever function occurs first. When the articulated lever achieves an approximately extended position, it no longer generates travel as the transmission ratio approaches infinity. In this situation, the lever takes over for the rest of the nominal force path. This is carried out with a constant transmission ratio and is determined by the position of the lever around the horizontal. The possible swivel angle prior to and subsequent to the horizontal position is approximately 20.degree.. The angular position is determined by the task at hand. With small nominal force paths, an eccentric lever may also be used instead of a lever.
An overload protection, such as is often required in mechanical presses with alternating transmission ratio according to the prior art, generally need not be installed in a press according to the invention. In the latter case, the transmission ratio remains constant in the nominal force range. The maximum force is determined by the force of the pressure-medium cylinder. The pressure medium is adjusted to the maximum system pressure by means of a pressure limiting valve. The maximum slide force is likewise determined in this way. Accordingly, in view of the absence of failure protection, a weakest point of the slide drive is established. The arrangement of a vertical pressure-medium cylinder in combination with the kinematics of the articulated lever drive makes possible within a confined space a mechanical drive allowing lift paths of more than 300 mm with a large nominal force path of up to approximately 100 mm at the same time.
The column damping arrangement, according to the invention, has a pressure piston and a pressure-medium cylinder with associated valves and supply storages. Operation of the column damping arrangement is initiated by the springing of the columns under load. The pressure piston is still not loaded at this time. Between the loaded column and the unloaded pressure piston there occurs a movement which allows pressure medium to flow from a supply storage into the mounted or fitted cylinder. For example, if the load is suddenly removed from the column after
REFERENCES:
patent: 2105053 (1938-01-01), Patrick
patent: 2204413 (1940-06-01), Hubbert
patent: 2916987 (1959-12-01), Hanni
patent: 4916932 (1990-04-01), Obrecht et al.
Feiereisen Henry M.
Jones David
Lehnhauser Hammerwerk GmbH
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