US2697592A - Booster apparatus for mining machines - Google Patents

Description

Dec. 21, 1954 F. B. MILLER BOOSTER APPARATUS FOR MINING MACHINES 4 sheets-sheet 1 Filed Sept. 2, 1950 INVENTOF Dec. 21, 1954 F. B. MILLER BOOSTER APPARATUS FOR MINING MACHINES Filed Sept. 2, 1-950 4 Sheets-Sheet 2 MN KN INVENTOE All Dec. 21, 1954 F. a. MILLER BOOSTER APPARATUS FOR MINING MACHINES 4 Sheets-Sheet 3 Filed Sept. 2, 1950 Dec. 21, 1954 F. B. MILLER BOOSTER APPARATUS FOR MINING MACHINES 4 Sheets-Sheet 4 Filed Sept. 2, 1950 INVENTOI? MWWWWWM United States Patent BOOSTER APPARATUS FOR MINING MACHINES Frederick B. Miller, Chicago, Ill.

Application September 2, 1950, Serial No. 182,955

7 Claims. (Cl. 262-12) The invention relates to mining machines adapted to undercut coal at the face of the mine, break down the coal that has been undercut and load the coal cuttings from the undercut and also the coal broken down above the undercut or kerf.

To accomplish the operation of breaking down the coal above the kerf by means of an hydraulic reciprocating dislodging member, it is known that greater pressures are required the deeper the dislodging member is forced into the coal face, so that to dislodge the coal toward the end of the stroke requires more pressure than at the beginning of the stroke. Of course, the installation could be designed for the maximum pressures required but the cost would be excessive for a competitive machine. Therefore, the invention contemplates an installation which will supply the average pressures required for breaking down the coal at the mine face and which will augment the same by booster mechanism that will derive energy from the return stroke of the dislodging member and deliver it at a predetermined instant in the forward stroke of said member.

Accordingly, a main object of the invention is to provide a booster cylinder adapted to become operative near the end of the working stroke of the dislodging member to provide that additional pressure required for driving said member into the coal face for its full working stroke.

Another object is to provide an accumulator in combination with the booster cylinder and which is charged by said booster cylinder since the accumulator receives a discllgarge of fluid from the booster cylinder on its. return stro e.

A further object is to provide means for interconnecting the booster cylinder piston with a main cylinder piston whereby the pressure actuated main cylinder piston on its return stroke imparts movement to the booster cylinder piston for returning the same.

Another object of the invention is to provide booster apparatus for a mining machine which has a reciprocatinc dislodging member for breaking down the coal at the mine face, wherein the booster ap aratus includes an accumulator that is charged with fluid at hi h pressure as a result of the return stroke of the dislod ing member, and wherein said accumulator is automaticallv dischar ed to the booster cvlinder toward the end of the working stroke. thus driving the dislodging member into the coal face f r its full stroke.

With these and various other obiects in View, the inven tion may consist of certain novel features of construction and operation, as will be more fully described and particularly pointed out in the specification, drawings and claims appended hereto.

In the drawings which illustrate an embodiment of the device and wherein like reference characters are used to desi nate like parts- Figure 1 is a plan view of a mining machine incorporating the improvements of the present invention;

Figure 2 is a side elevation of the machine of Figure'l taken on line IIII of said figure and showing the booster cylinder and in part section the hydraulic jack in conjunction with the anchor bars;

Figure 3 is an end elevation of the machine taken on line IIIIII of Figure 1 and showing the rear end of the main and booster cylinders;

Figure 4 is a transverse section of the conveyor, taken on line IVIV of Figure 1 and showing the conveyor in relation to the cu ter chains;

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Figure 5 is a fragmentary detail view, part elevation and part section, taken on line VV of Figure 1 and showing details of the hydraulic jack in conjunction with the anchor bars in retracted position;

Figure 6 is a diagrammatic view of the fluid circuit showing the tank, pump, main cylinder, booster cylinder, accumulator, and the valves for controlling flow;

Figure 7 is a fragmentary view of the quadrant gears, taken on line VIIVII of Figure l; and

Figure 8 is a plan view of Figure 7.

Referring to the details of the machine illustrated in the drawings, particularly Figure 4, the main frame 10 is pivotally mounted on transverse cross member 11, the said cross member being formed integral with a pair of longitudinal endless-tread supporting side frames 12-12 and which are provided with a front idler sprocket 13, a drive sprocket 14, and pivotally connected shoes 16 comprising the endless caterpillar treads 17, 17 of well known construction. The drive sprocket 14 is fixed to a drive shaft 15 which is driven by any suitable source of power. A second cross member 18 is formed integral with the side frames 12, 12. A pair of cylinders 19, 19 are piv otally mounted on the second cross member 18. A piston 20, reciprocably mounted in each of the cylinders 19, 19 is fixed to a piston rod 21, the said rod being in turn pivotally connected to the main frame 10. Hydraulic pressure is supplied to the cylinders 19 for tilting the main frame, it being understood that the hydraulic pressure may be derived from a fluid pump under the manual control of suitable valves.

A pair of cutter chain guides 22, 22, Figure l, is fixed to the forward end of the main frame 10 and in each of the guides there is operatively mounted a cutter chain 23 of usual construction, driven by sprocket 24 fixed to a drive shaft 25, said shaft being iournalled in housing 26, as best shown in Figure 2. Shoes 27. 27 are provided at the forward end of each cutter chain guide, being located on the top and bottom thereof, and the shoes are adapted to bear respectively against the top and bottom surfaces of the kerf, which is cut by the cutter chains upon operation thereof. A single endless conveyor belt 28, Figure 4, is driven by a pulley 29, said pulley being fixed to drive shaft 30, journalled in the rear of main frame 10. At its forward end the conveyor belt is trained over a pulley 31 journalled on a shaft 32, which is also fixed to the main frame at the forward end thereof adjacent to and in the path of the cutter chains 23, 23. Said chains are adapted to rake and crowd the cuttings onto the conveyor belt whereby said cuttings are delivered to the rear of the machine.

A pair of hydraulic jacks is associated with the cutter chain guides, each hydraulic jack including a cylinder 33, Figure 2, which extends through and is fixed to one of the cutter chain guides 22. The piston 34, reciprocably mounted in the cylinder 33, is provided with a piston rod 35. The head 36 of each piston rod 35 is suitably guided in the lower portion of its cylinder 33 and the rear end of an anchor bar 38 has interfitting and articulated relation with each piston rod head 36. The anchor bars 38 are each pivotally mounted in a slot 37 by means of a pin 39 and upon actuation of the piston 34 in a direction upwardly, the forward portion of the anchor bar is caused to en age and press against the floor of the mine. Each cylinder 33 is provided with openings 40, 40 to receive pi es through which pressure fluid may be supplied to the cylinder as by means of a fluid pump under manual control of suitable valves.

The combined action of the anchor bars in pressing downwardly against the mine floor and that of the shoes on the forward end of the cutter guides in pressing upwardlv against the to surface of the kerf locks the fmachine in a coal minin osi ion and the reactive forces caused by the thrusts of the dislod ing member are effectively resisted. For a more particular description of the anchoring means reference is made to my copending application Serial No. 171,135, filed June 29, 1950, and entitled Mining Machine.

Mounted on the main frame 10 is a mechanism for breaking down the coal similar to that shown and described in my prior Patent No. 2,368,863, dated Februthe rear of said cylinder.

ary 6, 1945. The mechanism consists of a pair of spaced upright supporting brackets 41 and 42, Fig. 3,'which journal the horizontal shafts 43 and 44 extending in spaced relation transverselyof the machine. Carriage guide members 45 and 46 are fixedly connected by the trunnion member 46a, and which provides means for journalling the guide members 45 and 46 on shaft 43. Quadrant gear 47 is keyed to shaft 44, said gear 47 having meshing relation with quadrant gear 48. Since gear 48 is integral with guide member 45, rotation of shaft 44 by any suitable source of power, not shown, will produce a swinging movement of the carriage guide members 45 and 46 with respect to shaft 43 as a transverse axis. The guide members are each provided with a bearing portion identified by numerals 49 and 50, respectively, on which ram bars .51 and 52 are slidably mounted. The ram bars form the sides of a reciprocable carriage, said bars being connected so as to complete the carriage by means of a carriage base plate 53. It will be understood that ram bars 51 and 52 are adapted to reciprocate in their respective bearing portion 49 or 50, which reciprocation is effected by the rack portions 54. which have meshing relation with rack pinions 55, keyed to the shaft '43. Said shaft 43 provides the drive shaft for oscillating the rack pinions 55, which may be driven in reversible directions by a source of power, not shown. A wedge plate 56, comprising'the coal dislodging member, isjsecured to the carriage base plate 53, and as the carriage is reciprocated to produce successivethrusts of the wedge plate the coal at the mine face is dislodged. Integral with the carriage base plate -53 are side cutters-59, 59 adapted to provide clearance for vertical'swinging movement of the wedge plate 56. g a

In operation of the mining machine as disclosed, the

main frame is fedforwardly to engage the cutter chains 23, 23 with the'coal face, and thereby cut a kerf in the coal face adjacent the floor of the mine. Cuttings from the kerf are raked backwardly and crowded onto the conveyor belt 28by the cutter chains. When the cutting 'of thekerf to a predetermined depth has been completed fluid is directed into the cylinders 33, 33 to impart movement to the pistons 34 thereof, and cause the forward end of the anchor bars 38, 38 to be pressed against the mine floor, thus locking the mining-machine in position for operation. To drive the wedge plate 56 into the coal to be mined requires hydraulic mechanism for reciprocating the carriage whereby thrusts ofthe wedge plate take place in succession. For each thrust the carriage is moved upwardlya predetermined extent from a lowermost forwardly inclined position. The invention provides an hydraulic booster cylinder in combination-with the hydraulic reciprocating mechanism for the wedge plate, said booster providing the additional force required for driving the wedge plate into the material to be mined for the full stroke of the carriage. described.

As best shown in Figure 6, the main cylinder 60 and the booster cylinder 61 are pivotally connected by means of pins 61a to the trunnion 460., which trunnion serves as a transverse connection for the guide members and 46. The main cylinder and the booster cylinder 61 are each provided with a piston 62 and 63, respectively, the said pistons having piston rods 64 and .65 and which are pivotally connected to the carriage base plate 53 by means of pins 65a. The main reservoir tank 66 is mounted on the main frame as is also the fluid pump 67, the selector valve 68, the accumulator 69, the pressure actuated valve 70, the relief valve 71, and the, check valves 72 and 73. Since the accumulator and valves are 'of known construction, it s not deemed necessary to describe'them in specific detail. Fluid line 74 connects the pump 67 to the tank 66. Fluid line 75 connects the pump 67 with the selector valve 68, whereas the selector valve This mechanism will now be v is connected to the forward end and to the rear end of the main cylinder 60 by lines 76 and 77, respectively. The said selector valve is also connected to the reservoir tank 66 by the fluid line 78. The pressure actuated valve 70 is connected to the accumulator '69 by fluid line'79and to the booster cylinder 61 by the fluid line 80. i The fluid line 81 connects the pressure actuated valve 70 'with line 77 and thus said 'valve' communicates and joins with the fluid connections to the main cylinder. Thefluid line 83 is provided with the check valve 72, the structure connecting the accumulator 69. with the booster cylinder 61 at FIuid line 84..is provided with the check valve 73, and through fluid lines and 8 2 the structure connects the rear of booster cylinder 61 with the reservoir tank 66. Oneach forward stroke of the booster cylinder fluid is withdrawn from the reservoir tank, the check valve 73 permitting such action. Connected to the forward end of the booster cylinder is a breather valve 85 of any known construction.

The carriage and thus the wedge plate 56 are reciprocated for breaking down the material to be mined by actuating the selector valve 68 so as to selectively direct pressure fluid from the fluid pump 67 to respective ends of the main cylinder 60. For example, to drive the carriage and the wedge plate in a forward direction, pressure fluid is admitted to fluid line 77 connecting with cylinder 60 at the rear thereof, and fluid line 76 is connected to reservoir tank 66 so that the forward end of cylinder 60 is simultaneously exhausted. As piston 62 of cylinder 60 is driven in a forward direction the piston 63 of the booster cylinder 61 will likewise move in the same direction. During forward travel of piston 63 the booster cylinder 61 is supplied with fluid from tank 66 by fluid line 82, check valve 73 and fluid line 30. To return the carriage and thus the wedge plate 56 the selector valve 68 is manipulated so as to supply pressure fluid to line 76 connecting with the forward end of cylinder 60. Simultaneously therewith line 77 will be connected to reservoir tank 66 so as to exhaust the rear of the cylinder. Piston 63 of the booster cylinder 61 will move in a return direction in unison with piston 62 of the main cylinder and during said return stroke fluid line 83 and check valve 72 are operative and fluid from the booster cylinder 61 is directed into the accumulator 69, the said fluid being forced into the accumulator against the tension of its coil spring and accordingly the accumulator is charged with pressure fluid on each return stroke of piston 63 of said booster cylinder 61.

In accordance with the invention the accumulator 69 is released to the booster cylinder at a predetermined point in the forward stroke of the wedge plate in order to supply additional pressure fluid for driving the wedge plate to complete its full working stroke in said forward direction. The pressure actuated valve 70 functions to control the release of the accumulator 69, the valve being interposed between the fluid lines 79 and 80 and having connection by means of fluid line 81 to the selector valve 68 and thus also communicating with the fluid line 77 which supplies pressure fluid to the rear of the main cylinder. Valve 70 is so constructed and arranged as to be responsive to a predetermined maximum pressure such as may be developed in fluid line 77. During the return stroke of said carriage and wedge plate 56, the fluid pressures developing in line 76 will be a minimum since the forces resisting travel of the carriage and wedge plate in a return direction are a minimum. However, as regards the forward working stroke of the wedge plate, higher operating pressures will develop in the fluid line 77 since the wedge plate encounters considerable resistance in being forced into the coal face to cause a breaking down of the coal being mined. This resistance to forward movement of the wedge plate progressively increases as the wedge plate is forced deeper and deeper into the coal face. Accordingly, toward the end of .the forward working stroke. the operating fluid pressures in the line 77 will reach a maximum and said working pressures may exceed the pressure of the fluid normally delivered by the pump, Since line 81 has connection with fluid line 77 the excessive fluid pressures developed therein are transmitted to the pressure actuated valve 70. Therefore as the wedge plate 56 reaches the end of its,working stroke in a forward direction, at which time it encounters the maximum resistance to its continued forward movement, the pressure actuated valve 70 is automatically operated to release the accumulator 69 to the booster cylinder 61. This supply of additional pressure fluid from the accumulator to the booster cylinder provides the additional force requircd to drive the wedge plate into'the coal to be mined for the full forward stroke of the wedge plate.

Upon 'completionof the breaking down of the successive portions of coal to a predetermined height above the kerf, the fluid in the cylinders 33-33 is released so that with the pressure on the anchor bars 3838 being removed the said bars can be reset in a horizontal retracted position. The mining machine is now free to be moved forwardly .tocut another kerf in the .coal face by operation of the cutter chains 23. As the mining machine is moved forwardly during a kerf 'cutting operation the broken down coal resting on the cutter chain guides 22-22 is moved up the inclined portion 57 onto the endless belt 28. The flared ribs 58--5 8, formlng part of the main frame 10, are adapted to guide the flow of coal into the path of said endless conveyor belt.

The invention is not to be limited to or by details of construction of the particular embodiment thereof illustrated by the drawings as various forms of the device w ll of course be apparent to those skilled in the art without departing from the spirit of the invention or the scope of the claims.

I claim:

1. In a mining machine having a main frame, guides mounted for vertical swinging movement relative to sa d main frame, a carriage reciprocably mounted in said guides and providing a dislodging member adapted to break down the material to be mined, a main cylinder and a booster cylinder having pistons respectively connected to the carriage for reciprocating the same, a fluid pump and a selector valve connected to the main cylinder for selectively supplying pressure fluid to respective ends of said cylinder for reciprocating its piston, a fluid reservoir and a check valve connected to the rear of the booster cylinder and operative to supply fluid to the cylinder as a result of forward travel of its piston, an accumulator and a check valve also connected to the rear of the booster cylinder whereby the accumulator is charged with pressure fluid from the booster cylinder upon the return stroke of its piston, other means for connecting the accumulator with the rear of the booster cylinder, said other means including a pressure actuated valve having communication with the connections to the main cylinder, and said pressure actuated valve operating automatically during the forward stroke of the carriage when a predetermined pressure exists in the connections to the main cylinder to connect the accumulator with the booster cylinder, whereby the said booster cylinder provides the additional force required to drive the dislodging member into the material to be mined for the full stroke of said member.

2. In a mining machine having a main frame, guides mounted for vertical swinging movement relative to said main frame, a carriage mounted for reciprocating movement in said guides and providing a dislodging member adapted to break down the material to be mined, a main cylinder having a piston connected to the carriage for reciprocating the same, a booster cylinder also having a piston connected to the carriage, selector valve means and connections leading to respective ends of the main cylinder for selectively supplying pressure fluid to said cylinder for reciprocating its piston, means connected to the rear of the booster cylinder and operative to supply fluid to the cylinder as a result of forward travel of its piston, an accumulator also connected to the rear of the booster cylinder, said connections including a check valve whereby the accumulator is charged with pressure fluid from the booster cylinder upon the return stroke of its piston, other means including a pressure actuated valve for connecting the accumulator with the rear of the booster cylinder, said valve having communication with the connections to the main cylinder, and said pressure actuated valve operating automatically during the forward stroke of the carriage as a result of a predetermined pressure increase developing in the connections to the main cylinder to connect the accumulator with the booster cylinder, whereby the said booster cylinder provides the additional force required to drive the dislodging member into the material to be mined for the full stroke of said member.

3. In a mining machine having a main frame, a dis lodging member mounted by the frame for reciprocating movement relative thereto, motor means for reciprocating said dislodging member to break down the material to be mined, said motor means including first and second cylinders, a piston mounted for reciprocation in each cylinder and operatively connected to said dislodging member, a fluid pump, means for selectively supplying pressure fluid from said fluid pump to re spective ends of the first cylinder for reciprocating the piston of said cylinder and thus the dislodging member, an accumulator, other means for directing fluid from the second cylinder to the accumulator on each return stroke of the piston of said cylinder, whereby the accumulator is charged with pressure fluid from said second cylinder, additional connections between the accumulator and said second cylinder, and a pressure actuated valve 111 said connections responsive to the operating fluid pressures of said pump, said valve operating automatically during the forward stroke of the dislodging member when the operatingfluid pressures of the pump exceed a maximum value to connect the accumulator with the second cylinder through said additional connections, whereby the second cylinder provides the extra force required to drive the dislodging member into the material to be mined for the full stroke of said member.

4. In a mining machine, in combination, a main frame, a carriage mounted by the frame for reciprocating movement, said carriage providing a wedge plate at its forward end for breaking down the material to be mined, hydraulic motor means for reciprocating the carriage including a main cylinder having a piston operatively connected to the carriage, a fluid pump providing a source of fluid under pressure, a selector valve for selectively directing the pressure fluid to respective ends of the main cylinder whereby to reciprocate its piston and thus the carriage, booster means for the carriage including a booster cylinder having a piston operatively connected to the carriage, an accumulator, means operative to charge the accumulator with pressure fluid from the booster cylinder on each return stroke of the piston of said booster cylinder, a release valve connected to said fluid pump and interconnected with said accumulator and said booster cylinder, said release valve being pressure actuated in response to a predetermined maximum pressure developed by said pump, whereby the accumulator is released to the booster cylinder during the forward stroke of the carriage to provide the additional force required to drive the dislodging member into the material to be mined for the full stroke of said member.

5. In a mining machine having a main frame, a dislodging member mounted by the frame for reciprocating movement relative thereto, motor means for reciprocating said dislodging member to break down the material to be mined, said motor means including a pair of hydraulic power cylinders supported by the frame and each having a reciprocating piston connected to the dislodging member, a source of fluid under pressure, a reservoir for said fluid, means for selectively supplying said pressure fluid to respective ends of one power cylinder for reciprocating the piston thereof and thus the dislodging member, an accumulator, a connection from the accumulator to the other power cylinder for supplying fluid from the other power cylinder to the accumulator on each return stroke of the piston thereof, whereby the accumulator is charged with pressure fluid when the dislodging member starts its forward stroke, a connection from the reservoir to said other power cylinder for supplying fluid thereto during the forward stroke of the piston thereof,.

a second connection between the accumulator and the other power cylinder for supplying pressure fluid from the accumulator to said other power cylinder, and valve means in the second connection for controlling the release of the pressure fluid from the accumulator.

6. In a mining machine, in combination, a main frame, a carriage mounted by the frame for reciprocating movement, said carriage providing a wedge plate at its forward end for breaking down the material to be mined, hydraulic motor means for reciprocating the carriage including a main cylinder having a piston operatively connected to the carriage, a source of fluid under pressure, a selector valvefor selectively directing the pressure fluid to respective ends of the main cylinder, whereby to reciprocate its piston and thus the carriage, booster means for the carriage including a booster cylinder having a piston operatively connected to the carriage, an accumulator, means operative to charge the accumulator with pressure fluid from the booster cylinder on each return stroke of the piston of said booster cylinder, a release valve having a conduit connecting said valve with the source of fluid under pressure, said valve being effective when actuated to release the accumulator to said booster cylinder, and said release valve being pressure actuated in response to a predetermined pressure developed in said connecting conduit, whereby the accumulator is released to the booster cylinder during the forward stroke of the carriage to provide the additional force required to drive the dislodging member into the material to be mined for the full stroke of said member.

7. In a mining machine, in combination, a main frame,

{a carriage mounted by the frame for reciprocating movement, said carriage providing a wedge plate at its forward end for breaking down the material to be mined, hydraulic "motor means for reciprocating the carriage including a -'main cylinder having a piston operatively connected to the carriage, a source of pressure fluid comprising a fluid pump connected to said main cylinder, a selector valve in said connection for controlling flow of said pressure fluid, booster means for the carriage including a booster cylinder having a piston operatively connected to the carriage, an accumulator, a first connection between the booster cylinder and the accumulator, a control valve in said first connection for trapping fluid in the accumulat'or and which is delivered thereto from the booster cylinder on each return stroke of the carriage whereby the accumulator is charged with pressure fluid, a reservoir also having a connection to said booster cylinder for supplying fluid thereto during the forward stroke of said carriage, a second connection between the accumu- References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,281,503 Levin Apr. 28, 1942 2,330,437 Lively Sept. 28, 1943

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