US3243964A

US3243964A - Mining apparatus

Info

Publication number: US3243964A
Application number: US272913A
Authority: US
Inventors: Thomas David Gurney Arnold; Carnegie James
Original assignee: Dowty Technical Developments Ltd
Current assignee: Dowty Technical Developments Ltd
Priority date: 1963-04-15
Filing date: 1963-04-15
Publication date: 1966-04-05
Anticipated expiration: 1983-04-05

Description

April 5, 1966 MINING APPARATUS 2 Sheets-Sheet 1 Filed April 15, 1963 m a 2, s s m m Mm H mz i J N13 1 vo bm E 95 6 n1 1 5 Wm m w. L1 t Iv:i tl::Iuf: M M H F .1 iii; x viz ET L, L m1 519m N 21 2% -92 N B N0 2 z 0 5 a g g Q i n an RV./ L: E :mm :mw NW NW .w :E ;H@ f doc 33% Q3 5 a WM 0 m h n m 5 7!: A O n April 1966 D. G. A. THOMAS ETAL 3,243,964

MINING APPARATUS 2 Sheets-Sheet 2 Filed April 15, 1963 mu 7 +6 I. C 2 Q A C 3 K11 T O "O b 2 m k Mu Ba 11 x A m @H INvENTafis PAW G,A- 77/oMA5 .1- TMES GARNEGIE' M! M United States Patent O 3,243,964 MINING APPARATUS David Gurney Arnold Thomas, Derhurst, and James Carnegie, (Zheltenham, England, assignors to Dowty Technical Developments Limited, Brockhampton Park, near Andoversford, England, a British company Filed Apr. 15, 1963, Ser. No. 272,913 9 Claims. (Cl. 61-45) This invention relates to mining apparatus.

In a mine, for example a coal mine, it is usual to arrange a series of roof supports along the working face of the mine and to advance the roof supports periodically towards the working face.

This invention relates to such mining apparatus in which the roof supports advance automatically in a predetermined sequence and each roof support is able to advance only when a predetermined signal has been obtained from the previous roof support in the sequence. Such a signal is preferably obtained from a support only when the support has satisfactorily completed its advancing operation, that is to say satisfactorily supports the roof at a position which is advanced towards the working face relative to the position of the roof support before the advancing operation began. A roof support which has failed to give a predetermined signal will be referred to as a failed roof support.

Circumstances causing a roof support to fail may be, for example, any one or more of the following:

(a) The roof support has failed to advance because of a fault in the advancing means associated with the support, or because a step in the floor of the mine prevents the advance, or because a conveyor, situated between the series of roof supports and the working face and which should have been advanced previously, has not advanced and therefore obstructs the advance of the roof support.

(b) The roof support has failed to satisfactoriiy support the roof after its advance because of a fault in the support extending means, because a hole has occurred in the roof above the support and the support has extended to its maximum height without satisfactorily supporting the roof.

Failure to receive the signal from a roof support causes the advance of the roof supports to stop, and it is an object of the present invention to provide an improved mining apparatus in which the advance of the roof supports need not necessarily cease until the fault causing the stoppage has been found and rectified.

The present invention provides mining apparatus including a series of roof supports arranged along the working face of a mine, means for automatically advancing the roof supports towards the working face in a predetermined sequence, each roof support being advanced after a predetermined signal has been obtained from the preceding support in the sequence, override means for causing the automatic-advancing means to emit a failed roof support from the sequence, and safety means responsive to selection of the override means and arranged to indicate a predetermined number of selections of the override means.

The safety means may indicate a predetermined number of selections of the override means corresponding to a predetermined number of failed roof supports randomly situated in the sequence, that is to say the safety means will indicate when a predetermined number of roof supports have failed, regardless of where they are situated in the sequence. The safety means may include a series of electrical relay circuits which are successively operated when each successive override operation is selected, the relay circuit corresponding to the override selection making up the predetermined number being arranged, when actuated to operate an indicating means.

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The safety means may indicate a predetermined number of selections of the override means corresponding to a predetermined number of failed supports adjacently situated in the sequence. For example, the safety means may indicate the failure of any two adjacent roof supports. The safety means may include an electrical relay circuit which is operated by the selection of the override means following failure of a roof support in the sequence and which is reset by the attainment of a satisfactory advancing operation of the next support in the sequence.

The safety means may indicate a predetermined number of selections of the override means by preventing any further override operations. Alternatively, or additionally, the safety means may indicate a predetermined number of selections of the override means by preventing further automatic advance of the roof supports.

One embodiment of the present invention will now be described, by Way of example, with reference to the accompanying drawings, of which,

FIGURE 1 is a diagrammatic view of a mining apparatus,

FIGURE 2 is an electrical circuit diagram of one part of the safety means, and,

FIGURE 3 is an electrical circuit diagram of another part of the safety means.

With reference to the accompanying drawing, a mining apparatus includes a series of roof supports 1 arranged along the working face 2 of a coal mine. A conveyor 3 extends along the coal face in front of the roof supports 1 and a cutting machine 4 is located in front of the conveyor 3. In the drawing, the cutting machine 4 is moving from left to right.

Each roof support 1 includes a floor beam carrying two or more hydraulically-operable props 5 which carry a roof beam 6. Each roof support 1 is connected to the conveyor 3 by a hydraulically-operable jack 7 by means of which the roof support can be advanced up to the conveyor 3. At least some of the jacks 7 may be doubleacting so that the conveyor 3 can be advanced relative to the roof supports 1. Alternatively, additional jacks may be secured between the roof support 1 and the conveyor 3 for advancing the conveyor 3.

The roof supports 1 are advanceable automatically towards the working face in a predetermined sequence. In this case each roof support is advanced successively, starting at the left hand end of the series. Means for automatically advancing the roof supports 1 includes an electro-hydraulic valve assembly (not shown) secured to each roof support. Each valve assembly can be electrically actuated to cause the props 5 to collapse thus lowering the support from the roof, the jack 7 to contract and ad- Vance the support towards the conveyor, 3, and then the props 5 to reset the support against the roof. When a satisfactory hydraulic pressure has built up in the props 5 after the support has been reset, this pressure causes a predetermined hydraulic-pressure signal to be emitted from the support.

Hydraulic fluid supply and return lines (not shown) extend along the face from a source of hydraulic fluid under pressure and are connected to the props 5 and jack 7 of each roof support 1.

The automatic advancing means also includes an automati'c-advance control 8 connected to each roof support 1 by wires 9. The automatic-advance control 8 is an electrical control and can send an electrical signal along the Wires 9 to the valve assembly of each roof support in turn to cause the roof support to undergo an advancing operation. A signal is not sent by the automatic-advance control 8 to a roof support until a predetermined hydraulicpressure signal, which indicates satisfactory completion of an advancing operation, has been received by the auto- 3 matic-advance control 8 along the wires 9 from the previous roof support in the sequence.

A mining apparatus as so far described has been more fully described in United Kingdom patent application No. 41622/61.

If .the signal is not received by the automatic-advance control 8 from a roof support 1 in the sequence, the automatic .advance of the roof supports 1 will stop. The min ing apparatus includes override means 11 for causing the automatic-advance means 8 to omit a failed roof support from the sequence. The override means 11 is manually operable and operation of the override means 11 sends an electric signal to the automatic-advance control 8 to cause the control 8 to select the next roof support in the sequence for advance without having received a signal from the failed roof support. 7 The mining apparatus further includes safety means 12 responsive to the selection of the override means and arranged to indicate a predetermined number of selections of the override means 11. p

One part of the safety means 12 is shown in FIGURE 2 and this part indicates a predetermined number of selections of the override means 11 corresponding to a predetermined number of failed roof supports randomly situated in the sequence, that is to say the part of the safety means 12 shown in FIGURE 2 indicates when a predetermined number of roof supports have failed, regardless of ,where they are situated inthe sequence. The part includes a series of electrical relay circuits N, O, V. Each relay has four associated contacts N1, N2, N3, N4, etc. FIGURE 2 shows the positions of the contacts when the relays are in the de-energised condition.

Contact 01 is actually made up of three sub-contacts a, b, and c. When relay solenoid is in the de-energised condition, contact a engages contact [1, and contact c is isolated. This condition of contact 01 is referred to as the open condition. When relay solenoid is energised, contact engages contact a and then disengages contact a from contact b. This condition of contact 01 is referred to as the closed condition. Contacts P1, Q1, V1 and N4 are similarly constructed.

Relay solenoids are connected in parallel with each other between a DO supply, the positive line being line 14 and the negative line being line 15. Relay solenoids are also connected in parallel with each other between line 15 and a line 16. Line 16 includes a normally open switch S2 and is connected to the DC. positive supply. Switch S2 is associated with the override means 11 and, when an override operation is selected by actuations of the override means 11, switch S2 is closed.

The line 14 includes a reset switch S1 which normally closes the line 14 but which can be operated to first connect line 17 to the DO. positive supply and then break the line 14. The line 17 is connected to relay solenoid The various relay contacts are arranged as shown in FIGURE 2. For example, between relay solenoid and line 16 are contacts 03 and N3 which are in series with each other and in parallel with contact P2 and subcontacts'a and c of contact Q1. Contact P2 and subcontacts a and c of contact Q1 are in series with each other. Contact P2 and sub-contacts a and b of contact Q1 are connected in series with each other between relay solenoid solenoid when the circuit through it is broken, and so render the circuit safe for use in a mine. The rectifiers connected between line 14 and the relay contacts and between line 16 and the relay contacts prevent unwanted interconnections which may otherwise occur.

The circuit also includes a rotary switch S3 by means of which the predetermined number of override selections which the circuit indicates can be varied. A rotary arm 18 can be rotated to contact any one of eight lines 19. Each line 19 is connected to a different one of the relay solenoids In FIGURE 2, the rotary arm 18 is contacting the line .19 connected to relay solenoid and, as will be described later, this means that the circuit will indicate when three override selections have been made.

An indicating means includes a relay solenoid connected between line 15 and the rotary arm 18 and controlling three contacts W1, W2, and W3 which are normally open but which close when relay solenoid is energised. Contact W1 is located in a warning circuit which contains, for example, a warning lamp or audible device, contact W2 is located in a circuit in the "automatic advance means 8, and contact W3 is located in a circuit in the override means 11.

In operation, reset switch S1 is switched to close line 17 and open line .14. This energises relay solenoid through line 17 and ensures that all the other relays are in t e de-en glsed condition. Energisation of relay solenoid closes contacts N1, N2 and N4 and opens contact N3. SWltCh S1 is then switched to close line 14 and open line 17. The relay solenoid holds on through contact N1 and line 14.

If a roof support fails, the operator selects an operation of the override means 11 and consequently temporarily closes switch S2. A circuit is then completed to relay solenoid through contacts U1 and N2, and relay solenoid is energised. Energisation of relay solenoid causes sub-contacts a and c of contact 01 to close and sub-contacts a and b of contact 01 to open, thus deenergising relay solenoid Also contacts 02 and 03 close and contact 04 opens.

De-energisation of relay solenoid opens contacts N1, N2 and N4 and closes contact N3. Thus relay solenoid holds on through 02 and line 14, and it will be seen that closure of contacts N3 and O3 prepares a circuit to relay solenoid In a similar manner, a second override selection energises relay solenoid de-energises relay solenoid and prepares a circuit to relay solenoid When a third override selection is made, a circuit is completed through line 16, contacts 04 and P3 and the relevant line 19 to relay solenoid which is therefore actuated to close contacts W1, W2 and W3. Thus the warning lamp or audible device operates, further automatic-advance of the supports is prevented and further override selection is prevented.

The advancing sequence can only be restarted by resetting the circuit by means of reset switch S1 and this switch is preferably operable only by operation of a lock and key device.

The part of the safety means 12 described with reference to FIGURE 2 indicates when a predetermined member of override selections corresponding to a predetermined member of randomly situated roof supports has been made. Alternatively or additionally, it may be desirable to provide safety means which indicates when a predetermined number of adjacent roof supports have failed. The part of the safety means 12 now to be described with reference to FIGURE 3 indicates when two adjacent roof supports have failed.

The part of the safety means 12 shown in FIGURE 3 includes three relays A, B and C connected in parallel with one another between a DC. supply. In the line between relay solenoid and the positive supply line are two switches PS and SS. Switch SS is closed by the selection of resetting of the props of a roof support and switch P5 is closed by the attainment of a satisfactory hydraulic pressure in the props after a roof support has been reset against the roof.

Relay solenoid can be connected to the positive supply line by any one of three possible paths. The first path includes normallyopen contact Al, the second path includes normally-open contacts B1, and subcontacts a and c of contact C2, and switch S2. Switch S2 is a switch which is close-d by selection of an override operation. The third path includes normally-open contact B1 and normally-closed sub-contacts a and b of contact C2. Relay solenoid can be connected to the positive supply line by two possible paths, one path including normally-open contact S2 and the other path including normally-open contact C1 and normally-closed contact A2.

A warning lamp 21 is connected between the negative and positive supply lines, the path between the lamp and positive including normally-open contact C3. Relay C may also include a further contact which when closed presents further operation of the automatic-advance control 8, in a manner similar to that described with reference to FIGURE 2.

FIGURE 3 also shows a fragment of the circuit of the override means 11. Switch S4 is the override selection switch which is ganged to switch S2 and B2 is a normallyopen contact controlled by relay solenoid In operation of the circuit shown in FIGURE 3, if a roof support resets satisfactorily against the roof, switches PS and SS are closed and relay solenoid is energised. Thus contact A1 closes to energise relay solenoid and contact A2 opens. Contacts B1 and B2 close. Relay B then holds on through contact B1 and sub-contacts a and b of contact C2. Closure of contact B2 thus prepares the circuit of the override means 11.

If the next roof support in the sequence resets satisfactorily against the roof to energise relay solenoid contacts PS and SS again close but relay solenoid is already energised.

If the next roof support in the sequence fails, at least contact PS does not close and relay solenoid is not energised. Thus contact A1 remains open and contact A2 remains closed. The override means is then operated by closing switch S4, which causes closure of switch S2. Thus relay solenoid is energised and holds on through contacts C1 and A2. C2 also closes to break contact between sub-contacts a and b and make contact between sub-contacts a and c. Consequently when contact S2 opens, relay solenoid is de-energised and contacts B1 and B2 open. Further, closure of contact C3 causes the warning lamp to operate and further advance of the support to be prevented.

Since contact B2 is open, the override means cannot 'be operated again if the next roof support fails, since cannot be energised. Also, if the next roof support fails, the Warning lamp remains on. If the next roof support advances and resets satisfactorily however, relay solenoid A B and 2 2 are once more energised with the result that relay solenoid C is de-mergised (thus extinguishing the warning lamp) and contact B2 closes to prepare the circuit of the override means.

After a failure of a roof support therefore, the circuit of FIGURE 3 is only reset if the neXt roof support in the sequence satisfactorily completes its advancing operation.

Thus the circuit of FIGURE 3 indicates when two adjacent roof supports have failed by causing the Warning lamp to remain illuminated and preventing the second failed roof support from being overridden, as well as preventing further operation of the automatic-advance means.

We claim as our invention:

1. Mining apparatus including a series of roof supports arranged along the working face of a mine and each providing a predetermined signal upon reaching asatisfactory roof supporting condition, automatic advancing means automatically advancing the roof supports towards the working face in a predetermined sequence in response to successive predetermined signals from adjacent supports in sequence, override means selectively operating to cause said automatic-advancing means to omit a failed roof support from said sequence, and safety means responsive to each operation of said override means indicating the occurrence of a predetermined number of operations of said override means.

2. Mining apparatus according to claim 1 wherein said safety means includes means indicating a predetermined number of operations of the override means corresponding to a predetermined number of failed supports randomly situated in said sequence.

3. Mining apparatus according to claim 2 wherein said safety means includes a series of electrical relay circuit means connected to be successively operated in response to each successive operation of said override means and including indicating circuit means coupled with a selected one of said series of relay circuit means and operable upon operation of said selected one to provide an indication that said predetermined number of operations of said override means has occurred.

4. Mining apparatus according to claim 1, wherein said safety means includes means indicating a predetermined number of selections of the override means corresponding to a predetermined number of failed supports adjacently situated in sequence. i

5. Mining apparatus according to claim 4 wherein said safety means includes electrical relay circuit means operated by the operation of said override means upon failure of a support in a sequence, and reset in response to a satisfactory advancing operation of the next succeedin support in said sequence.

6; Mining apparatus according to claim 1 wherein sairl safety means includes means responsive to a predetermined number of operations of said override means'to prevent any further override operations.

7. Mining apparatus according to claim 1 wherein said safety means includes means responsive to a predetermined number of operations of said override means to prevent further automatic advance of said roof supports.

8. A mining apparatus comprising in combination: a plurality of roof supports each providing a first signal upon achieving a predetermined first condition; roof support advancing means responsive only to said first signals occurring in a selected sequence to cause sequential advancement of said supports to said first condition; override means coupled with said advancing means and selectively operating to continue operation of said advancing means for sequential support advancement when one of said first signals in said selected sequence is not received by said advancing means; and safety means coupled with said override means providing an indication of the occurrence of a predetermined number of operations of said override means, whereby a warning is provided when a number of roof supports equal to said predetermined number have failed to achieve said first condition.

9. A mining apparatus in accordance with claim 8 wherein said safety means includes: a plurality of relays connected in circuit for sequential energization in response to repeated operation of said override means; indicating means; and switch means connected to said indicating means and to said relays and selectively adjustable to connect said indicating means in circuit with a selected one of said relays, whereby said indicating means is energized upon energization of a selected one of said relays.

References (Zited by the Examiner FOREIGN PATENTS 877,995 9/1961 Great Britain.

CHARLES 'E. OCONNELL, Primary Examiner.

EARL J. WITMER, Examiner. R. A. STENZEL, Assistant Examiner.

Claims

1. MINING APPARATUS INCLUDING A SERIES OF ROOF SUPPORTS ARRANGED ALONG THE WORKING FACE OF A MINE AND EACH PROVIDING A PREDETERMINED SIGNAL UPON REACHING A SATISFACTORY ROOF SUPPORTING CONDITION, AUTOMATIC ADVANCING MEANS AUTOMATICALLY ADVANCING THE ROOF SUPPORTS TOWARDS THE WORKING FACE IN A PREDETERMINED SEQUENCE IN RESPONSE TO SUCCESSIVE PREDETERMINED SIGNALS FROM ADJACENT SUPPORTS IN SEQUENCE, OVERRIDE MEANS SELECTIVELY OPERATING TO CAUSE SAID AUTOMATIC-ADVANCING MEANS TO OMIT A FAILED ROOF SUPPORT FROM SAID SEQUENCE, AND SAFETY MEANS RESPONSIVE TO EACH OPERATION OF SAID OVERRIDE MEANS INDICATING THE OCCURRENCE OF A PREDETERMINED NUMBER OF OPERATIONS OF SAID OVERRIDE MEANS.