DE1152376B - Hydraulic pit ram with enlarged stroke - Google Patents

Description

Fluctuations in the thickness of the seam as well as the occurring so-called convergence require a bracing element which has a certain stroke. With hydraulic pit rams, The largest possible stroke is desirable, especially for those with a smaller seam thickness.

The same absolute amount of variation in the distance between the hanging wall and the horizontal wall, the should be bridged by the stroke of the punch, makes with a punch of smaller inserted Length, as it is needed for seams of small thickness, a relatively larger lift is necessary than with a stamp with a large inserted length.

In order to achieve a large stroke with a certain length of the cylinder, it is already known to arrange several pistons telescopically one inside the other, either one after the other or also at the same time when filling the cylinder with a pressure medium move outwards and after draining of the pressure medium from the cylinder slide into each other again by weight or spring force.

The aforementioned arrangement has the disadvantage that when such a stamp sinks in each time, when one length of the telescopically arranged pistons is fully inserted and the next is begins to push in, the pushing force (load) must make a jump because the under hydraulic The effective area under pressure around the annular area of the next piston increases. Want the force or load that causes the insertion, however, is kept as constant as possible - and this is desirable within the narrowest possible limits for pit rams - so the hydraulic one would have to Pressure changed abruptly at each insertion stage, d. H. according to the additional pressure effective Area can be reduced. Although this is possible in principle, it would be complicated and time-consuming Require valve controls.

However, if the hydraulic pressure is not changed, there is firstly the disadvantage that it is ever Depending on the extent to which they sink into a row of punches, the individual punches differ considerably Can absorb load and that, secondly, the individual stamp in that Eininkstellung, in which the next piston is just beginning to slide in has a load jump. But both contradicts the mining requirement that the entire hanging surface should be supported as evenly as possible shall be.

There are also hydraulic pit rams be-hydraulic pit rams
with increased stroke

Applicant:

BWG mining and rolling mill mechanical engineering

GmbH,
Duisburg, Mercatorstr. 74

Oskar Noe, Mülheim / Ruhr-Speldorf,

Hermann Koppers, Mumeim / Ruhr-Dümpten,

and Friedrich Kämpken, Duisburg,

have been named as inventors

knows, in which one of several pistons plunging into a common pressure chamber is followed by a piston up and a piston extends downwards. The stroke is about half the stroke of the stamp according to the invention, since the two piston parts hinder each other in their length and not into one another or immerse in the pressure chamber side by side.

The invention relates to a hydraulic pit ram with several in a common Piston plunging in from above and below and not obstructing each other. The invention consists in the fact that the pistons are guided parallel to one another in the pressure chamber or slide into one another.

With a hydraulic pit ram constructed in this way, the disadvantages of the known telescopic rams and double rams are avoided. In comparison with the telescopic rams, the load on the ram is no longer changed abruptly without the need for complicated valve controls. Compared to the known double punches, a doubling of the stroke is achieved, since in the punch according to the invention the individual extendable piston parts do not interfere with one another.
With the same piston cross-section, the piston will theoretically extend simultaneously and evenly to both sides; practical, however, z. B. because of the friction differences in the implementation

309 650/52

Nmgsstellen (stuffing boxes) either the upper or extend the lower one first. By making the piston an arbitrarily small cross-sectional difference if you have it in your hand, extend the lower or upper punch first allow.

The embodiment according to the invention also offers the Possibility of stacking several punches, all of which have a double stroke, according to the modular principle, which can often be very advantageous in the special underground conditions.

Since it is fundamentally desirable that the head plate and foot plate on the largest possible area and support yourself against the hanging wall and the lying wall with even pressure distribution, it is advantageous to to connect these plates to the extending pistons in an articulated manner on all sides. With a hydraulic Pit punch according to the invention is achieved at the same time that the load pick-up is centric.

The drawing shows a schematic representation of some exemplary embodiments of the invention.

In Fig. 1 and 2 of the drawing, 1 denotes the cylindrical pressure space in which plunger 2 immerse from below and above, which move parallel to each other in the pressure chamber. Head- and base plates are indicated by 3 and 4. 5 and 6 are fill and drain valves, respectively.

3 and 4 show an embodiment in which the pistons 7 and 8 slide into one another. Of the Pressure chamber 1 is not cylindrical.

Another embodiment is shown in FIGS. 5 and 6 with a pressure chamber that is also not cylindrical. The pistons 9 are designed here as disc pistons.

Fig. 7 shows two hydraulic rams 10f, 11 placed one on top of the other to form a unit, which with their Head or foot plates 13 are braced obliquely between hanging and lying and yet the Pick up the load centrally.

Claims (5)

PATENT CLAIMS: 1. Hydraulic pit ram with several plungers dipping into a pressure chamber from above and below and thereby not obstructing each other, characterized in that the pistons (2) are guided parallel to each other in the pressure chamber (1) or slide one inside the other. 2. Hydraulic pit ram according to claim 1, characterized in that the sum the pressure-effective areas of the pistons immersed from above the sum of the pressure-effective areas Area of the piston immersed from below is almost the same. 3. Hydraulic pit ram according to claim 1 and 2, characterized in that the the upper and lower pistons slide into one another alternately. 4. Hydraulic pit ram according to claims 1 to 3, characterized in that The head and foot plates are the same as one another, and so are the end faces of the pressure chamber which emerge from the pistons have the same design. 5. Hydraulic pit ram according to claim 1, characterized in that the head and / or foot plates are movably arranged on the extending punch part. Considered publications:
U.S. Patent Nos. 2795 934, 2795 935, 057. 1 sheet of drawings ® 309 650/52 7.63