US3348381A - Coal face support systems - Google Patents

Description

Oct. 24, 1967 Filed Feb. 15, 1965 O. JACOBI GOAL FACE SUPPORT SYSTEMS 2 Sheets-Sheet l INVENTOR I UsKAR' JABEJEI.

BY dw ATT 1 Y S Oct. 24, 1967 o. JACOB! 3,348,381

COAL FACE SUPPORT SYSTEMS Filed Feb. 15, 1965 2 Sheets-Sheet 2 INVENTOR. [I SKAR JAB DB 1.

BY WM.

I ATTYS- United States Patent 3,348,381 COAL FACE SUPPORT SYSTEMS Oskar Jacobi, Semperstrasse 24, Essen, Germany Filed Feb. 15, 1965, Ser. No. 432,556 Claims priority, application Germany, June 4, 1964, B 77,067/64 6 Claims. (Cl. 61-45) ABSTRACT OF THE DISCLQSURE A method of successively advancing through a predetermined distance individual support units of a mine roof support system which are associated together in groups. The method provides for the shifting of the units in a particular group upon the need for local support adjacent that particular group, therefore, the groups are not advanced in sequential fashion. A group control means signals a unit control means of a group upon the sensing of a localized need for support. The unit control means then activates the first support unit in its group and the units within the group are advanced in a predetermined sequence. After advancing of the last unit within the group, the first unit again becomes the controlling unit and awaits a signal from the group control means prior to reactivation.

The invention relates to a method for successively shifting and setting the support units of a hydraulic coal face support system.

The method of the instant invention automatically secures the roof zone which is exposed at any given time, whether through the progress of the mining process or through breaking away of the working face, independently of the attention paid by the miner and immediately after the roof zone has been exposed.

The invention provides a method which eliminates, in particular, those danger factors which occur as a consequence of the roof not being supported at all times locally. This is achieved by advancing the support system not only in accordance with the progress of the working, which is customary in itself, but by also providing that any intentional or unintentional exposure of roof surface at any local point of the working face shall result in local advance of the support system.

This type of coal mine support does not exist in the methods of self-advancing step-by-step support heretofore employed, even when, in accordance with the latest proposals, the support units are shifted automatically and systematically in known manner by remote control, after each particular area has been worked. In this prior art method the shifting process takes place either after a breast or length of face has been worked, in which case that zone of the roof which is close to the coal face is left without support for a comparatively long time over this length, or not immediately after a strip has been worked but instead in succession in the longitudinal direction of the coal face in correlation with the advance of the winning machine. Even in the latter case it is not possible to make allowances for local changes in the conditions at the coal face, such as may occur, for eX- ample, due to scraping or breaking away of the working face. This may happen both during a working shift and when the coal face is not manned. If such a change occurs during the night shift, for example, it is possible that many hours may elapse before the exposed roof zone can be secured again.

It is the primary object of the instant invention to provide an improved method successively shifting and setting the support units of a coal face support system.

It is a further object to provide a method whereby any intentional or unintentional exposure of roof surface at any location along the working face shall give rise to control signals causing local advance of the support system.

Further objects of this invention will become apparent from the following specification and drawings, in which:

FIG. 1 is a diagrammatic plan view taken immediate- 1y below the roof of a coal mine, showing the method of the invention, and having parts broken away for clarity.

FIG. 2 is a diagrammatic view of a group control system.

FIG. 3 is a diagrammatic view of a single support unit control system.

Briefly, the method according to the invention consists in associating a plurality of support units of a hy draulic coal face support system together in groups in a manner known in the prior art. All the groups simultaneously seek contact with the working face and, in a first embodiment, one of the support units of each group is always at least partially relieved of roof supporting pressure at any given time to such an extent that, being under the forward pressure of a shifting device, it maintains contact with the advancing working face. The advancing unit of each group triggers a control device after completing an advancing movement of a predetermined distance. The signal operatively effects the immediate set ting of the support unit, which has just completed its advance, under the full roof-supporting load and also the successive relief of pressure in, and shifting of, the following or second unit. The following or second unit may then be regarded as having taken the place of the first unit as the controlling unit. After the second unit has completed its advancing movement through the predetermined distance, it ,actuates a control device and control system which sets the structural components of the second unit under its full roof supporting load and relieves the roof supporting load of the next unit as it begins its shifting or advancing movement. The process is repeated following on from unit to unit within the group in a predetermined cyclic sequence.

Thus, the support units associated together. in each group are shifted progressively in a sequence which is always constant as between the respective support units, until a support unit is reached which possibly has not yet completed its advancing movement but which has been relieved of roof supporting pressure by the signal transmitted by the preceding unit, whereupon the shifting process is halted in its progression from support unit to support unit, until this suport unit has likewise completed its advancing movement of the predetermined distance and the shifting of the following support units is then carried on until, after the last support unit in the group has been shifted, a changeover back to the first unit is made automatically.

It will be clear that the result thus obtained is that the shifting of each unit in the group takes place automatically after the shifting of the preceding unit, provided the zone of the roof to which that unit is allocated has been exposed in accordance with the stepping move ment when one unit advances. The remaining support units in the group secure the roof under the full roof supporting pressure.

In this connection, it is advantageous that the particular unit performing the stepping or self-advancing movement under the constant forward pressure of its shifting cylinder should be relieved of pressure only to such an extent that the sliding forward thereof under the action of the shifting device is just possible. Experience has shown that, with suiltable dimensioning of the shifting cylinder, this is the case at a setting pressure of 2 to 5 tons, which is fully adequate for fulfilling the purpose of protection against the falling-in of, for instance, loose lining from the roof.

The number of support units which are suitably combined together to form a group is chosen according to circumstances. In the case where pairs of props are employed it will as a rule be about 6 to 10 pairs of props.

The new method can be applied to support both by means of frame assemblies and by means of supporting trestles or yokes, both of the means being well known in the art.

Whether the shifting process is in the nature of an overhauling step or a follow-on step is of no importance from the point of view of the new method.

Normally a conveyor is disposed between the front vertical prop of each support unit and the coal face. Therefore, it is advantageous, and as a rule essential, in order to enable that unit which is the controlling unit at any given time to maintain contact with the working face, to design the roof bars of the support units, which maintain contact with the working face, so that they project forward comparatively far beyond the conveyor.

When in spite of the roof bar projecting forward comparatively far, the prop of the unit which is on the side where the working face is located is about to engage or strike the conveyor and the unit has not completed its advancing movement, the prop engages, for example, a feeler switch which is mounted adjacent the conveyor and the switch deactivates the hydraulic control system, thereby stopping the shifting process. This occurs before the predetermined stepping distance of the controlling unit has been reached so that the signal for further shifting is not transmitted, thereby the greatest possible safety for the exposed roof zone is still always achieved. After the conveyor has been moved, the controlling unit is free to complete its advancing movement.

The progress of the process of shifting the successive support units in the new method may be compared with a relay race in which many groups take part, but only one unit is in motion in each group and in each group group as a whole after the preceding one has run a predetermined distance.

In order to render satisfactory shifting of the partially pressure-relieved units and in order to prevent the floor or roof bar from remaining behind, shifting cylinders are preferably provided both in the roof region and in the floor region of the units.

The hydraulic, pneumatic or electrical control system which is required in order to produce the automatic occurrence of the various operations, namely, relief of pressure, shifting, and re-setting, in the chronological sequence prescribed by the invention, corresponds to systems which are known in the art, for example, in the field of remote control self-advancing support apparatus. Therefore, the control systems known in the art will not be described in detail in the present application. Preferably, provisions are made in any type of control system system and the controlling support unit is relieved of roof supporting pressure at that time. Immediately the controlling unit advances the predetermined distance and is reset under full roof supporting load. The next support unit is then actuated and the above procedure is repeated.

By means of an electric circuit or with a plurality of feeler devices it is also possible to cause the shifting operations within the group to proceed, not in a strict sequence, but in such manner that the unit which advances is always the one which has no contact with the coal face, while nevertheless there is always only one unit relieved of pressure at one and the same time. 7

Referring to FIG. 1, a coal face is generally indicated by the reference numeral 20. A plurality of support units 21 of a hydraulic coal face support system are associated together to form groups. In FIG. 1, three such groups are shown and indicated by the Roman numerals I, II, and III. FIG. 1 shows diagrammatically various conceivable stages in the shifting operation as carried out by the method of the invention, when applied to the simple case of a fixed cyclic sequence, all details not essential to the understanding of the invention having been omitted.

FIG. 1 shows three groups of support units (I, II, and III) following one on the other on the dip or Working, the groups each consisting of ten support units 21. For purposes of explanation the ten support units 21, of each i group, are serially numbered from 1-10 in FIG. 1.

used in practicing the instant method for carrying out the control operations manually when necessary or desired.

As described above, if the working face has not receded the predetermined distance adjacent the controlling support unit, it is possible that the controlling unit will remain partially relieved of pressure fora long time while concurrently remaining under the constant forward pressure of the shifting device. This condition could exist, for example, where the excavation of the coal face proceeded at an abnormally slow pace. To eliminate this condition, while practicing the instant method, according to the preferred embodiment; a feeler device is mounted on the end of the controlling support unit. The feeler device is mounted adjacent the roof bar of the support unit, as described below. The feeler device maintains continuous contact with the working face. When the predetermined distance is sensed, the feeler device signals the control In FIG. 1, the roof support props are not shown but their location is indicated by circles drawn on top of the roof bars of the support units 21. If the circle is cross hatched, this indicates that the prop is under full roof supporting pressure. However, if the circle is not filled the prop has been at least partially relieved of roof supporting pressure.

The first group of support units (I) is in the initial state, that is to say, all the support units 1 to 10 are in a' position close to the working face. The topmost support unit 1 in this group (I) which in the condition shown constitutes the controlling unit, is relieved of pressure. Under the constant forward pressure of its shitting cylinder the unit 1 is in contact with the working face 20. Its roof bar is pressed constantly against the working face 20.

However, in the preferred embodiment, the controlling support unit, in this instance the unit 1, is not relieved of pressure until the predetermined advancing movement is sensed by the feeler device. One embodiment of a known feeler device is generally indicated in FIG. 2 by the reference number 25. A known pneumatic group control system is generally indicated by the reference number 26 and a known frame or support unit control system is indicated by the reference number 27. The feeler device 25 includes a pneumatic cylinder 30 which is mounted adjacent a roof bar of, for example, the support unit 1. The cylinder 30 includes a piston 31, a piston rod 32, which mounts a feeler 33, and fluid ports 34 and 35. A projection 36 having a cam surface 37 is connected to the rear of the piston rod 32. V

A three way valve 3-8 having a valve spool 39 is mounted adjacent the cylinder 30. A valve activating rod 40 extends outwardly from the valve 38 in a position where it can be engaged by the cam surface 37.

The group control 26 includes a cyclic timer unit 41 which directs compressed air from an air supply line 42 to conduits 43, which are in communication with the controlling unit of each of the groups, for examples, the groups I, II and III.

As depicted in FIG. 2, the air supply line 42 is in communication with a conduit 44 through the unit 41, and the conduit 43a. The conduit 44 is connected to the port 35 of the cylinder 30 and a conduit 45 extends from the conduit 44 to the valve 38.

A constant pressure airline 46 is connected to the port 34 of the cylinder 30. An air conduit 47 extends between the valve 38 and the support unit control system 27 and a conduit 48 extends outwardly from the valve 38.

In operation, the constant pressure air from the airline 46 urges the piston 31 to the right. FIG. 2 depicts the condition immediately after the cyclic timer 41 has operatively connected the conduit 44 to the supply line 42. The compressed air of the supply line 42 is of a higher pressure which overrides the air pressure from the airline 46 and the piston 3-1 is urged to the left (as shown in FIG. 2). As the feeler 33 moves to the left, if it moves the predetermined advancing distance prior to engaging the coal face, the cam surface 37 strikes the valve activating rod 40. This moves the valve spool 39 downwardly placing the supply line 42 in communication with the air conduit 47 which activates the individual support unit control system 27 as described below.

On the other hand, if the feeler 33 does not move the predetermined distance, when the timer 41 cycles to the next group, the air pressure in the conduit 44 collapses and the piston 31 moves to the right. When this occurs, the individual unit control system 27 of group II is not activated.

It should be noted that when the individual control system is actuated, the group control 26 does not wait until the all of the individual support units (1-10) in the group II have been activated, but rather, cycles throughout the feeler devices of the remaining groups so that localized support is provided by any group in which the coal face is spaced the predetermined distance, irrespective of the position of that group with respect to the remaining groups.

Referring to FIGS. 2 and 3, if the valve spool 39 is moved downwardly, air is supplied to the conduit 47 leading to the respective unit control system 27. A valve 50 in the conduit 47 is activated and a supply line 51 is placed in communication with a conduit 52 which leads to a stepping relay 53 of the unit control system 27. The air pressure activates the relay 53 and moves a controller 54 from a start position indicated by the dashed line position 54 to the full line position, wherein the number 1 support unit, of the support units 21, is activated.

Each of the support units 21 includes a control device 55 which in the present embodiment is in electrical communication with the stepping relay 53.

A pair of roof props 56 having roof bar rarns and an advancing cylinder, all of which are well known in the art, are operatively connected to the control device 55. Upon activation of the number 1 support unit, its rams are depressurized, and its advancing cylinder is operated advancing the props 56 the predetermined distance. Upon advancing the rams are repressurized and the control device 55 is triggered thereby transmitting a signal back to the unit control system 27 The stepping relay 53 is activated and the controller 54 is operatively connected to unit number 2. The process is repeated from unit to unit in a predetermined sequence until the start position, indicated by the dashed line position of the controller 54, is reached. At this time, air is supplied through a conduit 58 and through the conduit 48 to shift the valves 50 and 38. Unit number 1 is again the control unit at this time and is reactivated upon the sensing of the predetermined distance by the feeler device 25 of group II as described above.

As previously mentioned, if during the advancing movement the props 56 contact the conveyor, indicated by the reference number 60 in FIG. 3, a feeler switch is activated which transmits a signal to the respective control device 55 which stops the shifting movement. Movement within that particular group does not begin again until the conveyor 60 has been moved.

According to the embodiment, the middle units 4 to 7 of group I are opposite an excavation in the working face and therefore do not have any contact with the face 20. In this example they cannot be shifted before all the preceding units have been shifted. As previously mentioned, it is possible to allow for this by using a special electric circuit. As the entire length of the group of support units 1 to 10 along the dip measures only about 8 metres, no moments of danger occur because of this. By choosing smaller groups the roof areas which may possibly be unsupported can be further reduced. In the case of this example, the shiftingsignal for the unit 1, which signal initiates the shifting process of the entire group, is transmitted only when either the excavation shown has advanced to a point beyond that zone of the face 21 to which the unit 1 is allocated, or the corresponding roof zone has been exposed by the winning operation.

In the first case, on the assumption that the extent of the excavation remains unchanged at the lower end of the section to which the group I is allocated, the shifting process would continue only as far as the unit 7, while successive shifting of the remaining units 8 to 10 would mean that the roof zone would be exposed in this region also.

In the case of the second group (II), the drawing shows that the upper units 1 to 4 of the group (II) have already been progressively shifted through the predetermined distance and the unit 5 has been relieved of pressure by the signal transmitted by the unit 4 (this being indicated by the circles which represent the props not being filled in). In the state of the working face illustrated, in which the corresponding roof zone is exposed, such unit 5, after being shifted the stepping or advancing distance and being set by the signal then produced so as to take full load, transmits the shifting signal for the following units 6 to 10.

In the case of the third group of support units (III), it is assumed that the topmost unit 1 has been relieved of pressure and has already been partially shifted but has not yet completed its prescribed advancing movement, because it has already been brought to a stop by the insufficiently exposed face before it has traveled its predetermined distance. Thus, this unit remains relieved of pressure and under the continuous action of its shifting mechanism which presses it forward until such time as the adjacent roof zone has been exposed, whereupon the process is continued as has been described.

The instant invention provides for automatically and immediately securing to as great an extent as possible the zone of the roof which is exposed by excavation from the face 20. Only a single support unit is relieved of pressure at any one time and it is only partially relieved. As such it still can perform its roof supporting function.

Of course, the invention is not limited to the particular manner of carrying it into effect described above in detail. Thus, in cases where it proves to be expedient, the sequence in which the support units are shifted can be varied. For example, instead of the controlling unit controlling the unit immediately adjacent to it, the next unit is by-passed and the following unit is controlled. The control operation thereafter may revert to the intermediate unit if this proves to be expedient in certain circumstances, for example in order to avoid loading of partially pressure-relieved frames due to convergence effects, such as would prevent the shifting operation. In this arrangement likewise, the control signal is always transmitted in the same direction in a closed cycle.

What I claim is:

1. A method of automatically and successively advancing through a predetermined distance individual support units of a mine roof support system which are associated together in groups, the groups being controlled by a group control means, and wherein the individual support units within each group are controlled by unit control means, comprising transmitting a signal from the group control means to the unit control means of each group which is spaced the predetermined distance from the working face, whereby the unit control systems are actuated upon the localized sensing of the predetermined distance rather than sequentially, each of said actuated unit control means transmitting a signal to a first one of its individual roof support units, relieving the first support unit of its roofsupporting pressure, advancing the first support through the predetermined distance, triggering the unit control means, resetting the first unit under its roof-supporting pressure, relieving the second one of the individual roof support units of its roof-supporting pressure, the unit control means relaying control signals from unit to unit until the last unit is reached whereupon the first unit again becomes the controlling unit and is reactuated upon a subsequent signal from the group control means.

2. A method according to claim 1, wherein the signal transmitted by the group control means occurs upon sensing of the predetermined distance between the controlling support unit of a group and the coal face by feeler means.

3. A method according to claim 1, wherein within each group, the control signals for the advancing action are transmitted from unit to unit sequentially in one direction only, from the first unit of the group as far as the last unit thereof, and from this last unit back to the first unit.

4. A method according to claim 1 wherein the particular individual support unit performing the advancing action at anytime is relieved of pressure only by the amount which permits it to slide forward under the action of its shifting device.

5. A method according to claim 1 wherein conveyor means are positioned between the support units of the group and the coal face, including the step of stopping the advancing movement of the individual support units; upon engagement of the advancing unit and the conveyor means.

6. A method for supporting amine root with a hydraulic working face support system having a plurality of support groups controlled by a group control system, each of the support groups; comprised of a plurality of individual support units which are controlled by a support unit control system, each of said support units hav ing shifting means for advancing the unit toward the working face and prop means operable at various roof supporting pressures, comprising, transmitting a signal from the group control system to at least one of the support groups to activate individual ones of the support unit control systems, whereby the individual support unit control systems are actuated upon a need for localized roof support rather than sequentially, at least partially relieving a first one of the support units from the support group of its full roof-supporting pressure, subjecting the relieved first support unit to a continuous forward shifting pressure, moving the first roof-supporting unit toward the working face a predetermined distance, triggering the support unit control system upon completion of the movement of the first unit through the predetermined distance, whereby the support unit control system effects the setting of the first unit under its full roof supporting load and relieving a second support unit of the group from its full roof supporting pressure, whereby said second unit is the controlling unit, the support unit control system relaying control signals for the advancing action from unit to unit in a predetermined sequence until the last unit is reached whereupon the control signal is relayed back to the first unit.

References Cited UNITED STATES PATENTS 3,202,058 8/1965 Bolton et al. 6l45.2 X 3,243,964 4/ 1966 Thomas et al 6145.2 X 3,259,024 7/ i966 Kibble et al. 6l45.2 X 3,272,084 9/1966 Bolton et al. 6145.2 X

DAVID J. WILLIAMOWSKY, Primary Examinen JACOB SHAPIRO, Examinem UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,348,381 October 24, 1967 Oskar Jacobi ror appears in the above numbered pat- It is hereby certified that er the said Letters Patent should read as ent requiring correction and that corrected below.

Column 1, line 63, for "scraping" read scarping column 2, line 10, after "the" insert instant line 51, for "suport" read support line 71, for "suiltable" read suitable column 3, line 40, after "group", second occurrence, insert one unit relieves the preceding one in the motion of the Signed and sealed this 12th day of November 1968.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents Edward M. Fletcher, Jr.

Attesting Officer

Claims (1)

1. A METHOD OF AUTOMATICALLY AND SUCCESSIVELY ADVANCING THROUGH A PREDETERMINED DISTANCE INDIVIDUAL SUPPORT UNITS OF A MINE ROOF SUPPORT SYSTEM WHICH ARE ASSOCIATED TOGETHER IN GROUPS, THE GROUPS BEING CONTROLLED BY A GROUP CONTROL MEANS, AND WHEREIN THE INDIVIDUAL SUPPORT UNITS WITHIN EACH GROUP ARE CONTROLLED BY UNIT CONTROL MEANS, COMPRISING TRANSMITTING A SIGNAL FROM THE GROUP CONTROL MEANS TO THE UNIT CONTROL MEANS OF EACH GROUP WHICH IS SPACED THE PREDETERMINED DISTANCE FROM THE WORKING FACE, WHEREBY THE UNIT CONTROL SYSTEMS ARE ACTUATED UPON THE LOCALIZED SENSING OF THE PREDETERMINED DISTANCE RATHER THAN SEQUENTIALLY, EACH OF SAID ACTUATED UNIT CONTROL MEANS TRANSMITTING A SIGNAL TO A FIRST ONE OF ITS INDIVIDUAL ROOF SUPPORT UNITS, RELIEVING THE FIRST SUPPORT UNIT OF ITS ROOFSUPPORTING PRESSURE, ADVANCING THE FIRST SUPPORT THROUGH THE PREDETERMINED DISTANCE, TRIGGERING THE UNIT CONTROL MEANS, RESETTING THE FIRST UNIT UNDER ITS ROOF-SUPPORTING PRESSURE, RELIEVING THE SECOND ONE OF THE INDIVIDUAL ROOF SUPPORT UNITS OF ITS ROOF-SUPPORTING PRESSURE, THE UNIT CONTROL MEANS RELAYING CONTROL SIGNALS FROM UNIT TO UNIT UNTIL THE LAST UNIT IS REACHED WHEREUPON THE FIRST UNIT AGAIN BECOMES THE CONTROLLING UNIT AND IS REACTUATED UPON A SUBSEQUENT SIGNAL FROM THE GROUP CONTROL MEANS.

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