DE8615599U1 - Device for shock-like acceleration of masses - Google Patents

Description

Hellmuth Walte*f'GmbH 23Ö'o Kiel 16 October 1989

Projensdorfer Str. 324 23oo Kiel 1

Device for the rapid acceleration of ingots

The invention relates to a

Device for the shock-like acceleration of masses by means of a lifting table, which is actuated by the sudden relaxation of a pre-tensioned spring.

In the known designs of this type, there is a mechanical spring in the lifting table, for example a disc spring package. This spring is tensioned by compression and suddenly relaxed to produce a shock-like acceleration of the lifting table.

The disadvantage of the known designs is, on the one hand, that mechanical springs with different characteristics must be available for replacement for the required different acceleration forces and relaxation curves and, on the other hand, that with masses to be accelerated in the order of several tons in total weight, the acceleration forces become so large (2ρ<ρρρρ) that mechanical springs reach such dimensions that effortless handling when replacing them is no longer possible.

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The aim of the invention was therefore to devise a device that would eliminate the problems of replacing or handling mechanical springs when large masses are to be accelerated.

This object is achieved by the device according to the invention in that the acceleration force can be stored in an oil pressure accumulator acting as a hydraulic spring in such a way that the lifting table is designed as a piston which is immersed in a pressure-tight manner in an initially pressure-free displacement chamber filled with oil, that the displacement chamber and the oil pressure chamber are connected to one another via at least one connecting line, preferably two connecting lines, and that a controllable valve is provided for opening and closing the cross sections of the two connecting lines.

This is possible because an oil volume enclosed in a vessel has an almost linear elasticity characteristic up to a pressure of about 4oo-5oo bar. By changing the pressure, the maximum spring force can be adjusted, and by changing the storage volume, the spring travel can be adjusted to the desired level.

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One of the problems is that the oil trapped in the oil pressure accumulator can be released so quickly through a valve that the pressure required for maximum acceleration builds up suddenly in the displacement chamber ( &zgr; 1 ms), and the valve also releases such a large cross-section that the oil can freely expand from the pressure accumulator into the displacement chamber without any significant resistance. It must be taken into account that the mass has a high speed at the end of the acceleration phase and the oil flow is correspondingly large.

To solve this problem* it is advantageously proposed that the valve is designed as an axially displaceable double slide sleeve with low mass, that two control edges are provided on the slide sleeve, which simultaneously release the flow cross-sections of the two connecting pipes, and that the axial stroke of the slide sleeve consists of a pre-run and an opening or closing path.

Due to the advance path of the slide sleeve until the beginning of opening, it receives a pre-opening speed which i

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Claims (3)

-4 &diams; · ' e * · · &bull; · · Hellmuth Walter GmbH Projensdorfer Str. 324 23oo Kieltr« · ·&bull;«10.Oktober2'S198?111&lgr;&bull; · · &igr; Kiel,I i . i F C . · den pns prU ehe 1) Device for the shock-like acceleration of masses by means of a lifting table which is actuated by suddenly relaxing a pre-tensioned spring, characterized in that the acceleration force can be stored in an oil pressure accumulator (4) acting as a hydraulic spring such that the lifting table (2) is designed as a piston which dips pressure-tight into an oil-filled, initially pressure-free displacement chamber (3), that the displacement chamber (3) and the oil pressure chamber (4) are connected to one another via at least one connecting line, preferably two connecting lines (8) and (S), and that a controllable valve is provided for opening and closing the cross-sections of the two connecting lines (8) and (?). 2) Device according to claim 1, characterized in that the valve is designed as an axially displaceable slide sleeve (5) with low mass, that two control edges (6) and (7) are provided on the slide sleeve (5), which simultaneously release the flow cross sections of the two connecting lines (8) and (?), and that itiri in Ii &igr;« ! 5 Jl if* the axial stroke of the thrust sleeve (5) consists of a pre-travel and an opening or closing path* 3) Device according to claim 2, characterized in that the double slide sleeve (5) is fastened centrally to a slide control cam (θ) by means of webs releasing openings (15) and (14). asasakiiiiB *r «..«..iiiil.