DE1083104B - Hydraulic pressing device for rolling mills - Google Patents

Description

GERMAN

The invention relates to a hydraulic pressing device for rolling mills with constantly conveying Pump in which the contact pressure, regulated by means of a spring-loaded overflow valve, is changed the spring preload is adjustable and between the overflow valve (control valve) and Working cylinder a check valve is provided.

Hydraulic forces are used to regulate the forces in rolling mills because they are easy to adjust Devices. The hydrostatic system is simple in structure, but the forces change even at low levels Temperature fluctuations. This keeps the operator's attention constantly in Availed. The hydrodynamic system with a constantly pumping pump is something of a construction more complicated, but has the great advantage that the once set on a pressure regulating valve Pressure remains constant without special monitoring. Despite this crucial advantage, this is hydrodynamic System has so far been used little because the pressure regulating valve generates high frequency vibrations and acts on the working piston were transferred and because the working piston against unwanted displacement from the working side was secured.

The invention is based on the object of the roller pressure in the aforementioned hydrodynamic system without reversing the pressure piston, with the disadvantages listed above do not occur. According to the invention, there is a free passage with a small cross section in the check valve present between the two sides of the closure body.

The drawing shows schematically as examples an embodiment of the invention, wherein a pressure reducing valve and two check valves in section on a much larger scale than the other parts are shown.

A constantly pumping pump 1 conveys oil through a line 2 from a tank 3 to a pressure relief valve ^ which is provided with a reflux line 5 to the tank 3. Arrived from the pressure relief valve 4 the oil via a line 7 to the four-way valve 8, in the position shown of the operating lever 9 is the Line 7 is connected to a line 10 with a pressure regulating valve 11 of known type. Further is a line 12 from the release side of a double-acting piston 13, which is in a cylinder 14 moved, connected by the four-way valve 8 to a line 15 to the tank 3. When turning of the lever 9 in the position 9 ', the lines 7 and 12 on the one hand and 10 and 15 on the other hand are connected.

The line 10 is at an input chamber 16 in

Hydraulic pressing device
for rolling mills

Applicant:
Bühler Brothers, Uzwil (Switzerland)

Representative: Dr. K. Schwarzhans, patent attorney,
Munich 19, Romanplatz 9

Claimed priority:
Switzerland from November 26, 1955

Ernst Bossahrd, Steinacker, Uzwil (Switzerland),
has been named as the inventor

Housing of the pressure reducing valve 11 connected. The input chamber 16 is through a bore 17 connected to an outlet chamber 18.

From this output chamber 18 a line 20 leads via a check valve 21 to the pressing side of the Piston 13, which the pressure generated on the element to be regulated, for. B. on a roller or on a friction bar, transfers. The check valve 21 is necessary to prevent any Transferring pressure fluctuations in the pressure regulating valve 11 to the piston 13.

In the housing of the pressure regulating valve 11, a piston 23 is guided, the heads 24 and 25 resemble Has diameter as the bore 17. These heads 24 and 25 are smaller by a rod 26 Connected diameter. The head 24 is loaded by a spring 28 and is under the influence of the pressure in a compensation chamber 29. When the piston 23 moves against the force of the Spring 28, the head 25 can close the bore 17. This head 25 has bores 31 and 32 large Diameter so that its lower side is under the influence of the pressure in the output chamber 18. The bore 32 is connected to the compensation chamber 29 through a bore 33 of small diameter. The compensation chamber 29 is through a bore 35 with a pressure relief valve, for. B. a ball 36, connected. The ball 36 is loaded by a spring 37, the force of which is adjustable with a screw 38 is. The pressure relief valve is connected to the tank 3 by a return line 39.

A valve piston 42 loaded by a spring 41 is guided in the housing of the check valve 21. He has a notch 43 so that a free passage

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small cross-section between the two sides of the check valve 21 is present.

A line 45 is branched off from the line 20. It runs from the pressure side of the piston 13 over a check valve 46 to the high pressure chamber 16 of the pressure regulating valve 11. In the housing of the check valve 46, a valve piston 47 loaded by a spring 48 is guided.

The device works in the following way: The operating lever 9 is in the drawn xo Location; the roller or the friction bar is pressed on by the piston 13. To increase the contact pressure, the screw 38 is tightened, which increases the response pressure of the ball valve 36. The accordingly higher pressure in the output chamber 18 is transmitted via the check valve 21 to the pressure side of the piston 13. When the pressure in the outlet chamber 18 exceeds the response pressure of the ball valve 36 exceeds, this ball valve 36 opens, and part of the oil in the equalization chamber 29 can over the Line 39 flow back to tank 3. This drops the pressure in the equalization chamber 29, and there the bore 33 has only a small diameter, the piston 23 moves against the force of the spring 28. The Cross section of the throttle point between the bore 17 and the head 25 is reduced. In operation a constant, low oil pressure flow via the bore 33, the compensation chamber 29, the bore 35, the ball valve 36 and the return line 39 a. Thanks to this little constant reflux, the Pressure at its set value.

In order to reduce the pressing force, the screw 38 is loosened somewhat. This reduces the Response pressure of the ball valve 36, and the pressure in the output chamber 18 falls accordingly. thanks to the notch 43 can slowly transfer this pressure reduction to the pressure side of the piston 13,

When a harder piece is being ground, the check valve 21 prevents the roll or billet is repulsed. The desired pressure can be set slowly above the notch 43.

In order to loosen the roller or the friction bar, it is sufficient to move the operating lever 9 to the dot-dash line Turn position 9 '. So that the lines 7 and 12 are connected, and the pressure oil reaches the Release side of the piston 13. The oil on the pressure side of the piston 13 can be via line 20, line 45, Check valve 46, high pressure chamber 16, line 10, four-way valve 8 and return line 15 to Tank 3 flow back.

The device is particularly suitable when several pressure regulating valves 11 with a single pressure relief valve 4 are interconnected.

The device described allows the contact pressure to be increased both continuously and continuously to diminish. It also ensures that the contact pressure is released properly.

The objects for which no protection has been requested do not belong to the invention.

Claims (1)

Claim ·. Hydraulic pressing device for rolling mills, especially for grinding chocolate, Paint and soap, with a constantly pumping pump, in which the by means of a spring-loaded Overflow valve regulated contact pressure of the rollers by changing the spring preload is adjustable and a check valve between the overflow valve (control valve) and the working cylinder is provided, characterized in that a free passage in the check valve (21) (43) small cross-section is present between the two sides of the closure body (42). Considered publications:
German Patent No. 946 676;
British Patent No. 715,806;
Belgian patent specification No. 517 899. 1 sheet of drawings © 009 529/145 5.60