US 2776040 A
Description (OCR text may contain errors)
Jan. 1, 1957 c. H. SNYDER CONTINUOUS AUTOMATIC FLEXIBLE CONVEYER 5 Sheets-Sheet 1 Filed March 27, 1952 Jan. 1, 1957 c. H. SNYDER 2,776,040
CONTINUOUS AUTOMATIC FLEXIBLE CONVEIYER Filed March 27, 1952 5 Sheets-Sheet 2 Jan. 1, 1957 c. H. SNYDER 2,775,040
CONTINUOUS AUTOMATIC FLEXIBLE CONVEYER Filed March 27, 1952 5 Sheets-Sheet 5 Jan. 1, 1957 c. H. SNYDER CONTINUOUS AUTOMATIC FLEXIBLE CONVEYER 5 Sheets-Sheet 4 Filed March 27, 1952 MNN WNN
W N mow m Jan. 1, 1957 c. H. SNYDER CONTINUOUS AUTOMATIC FLEXIBLE CONVEYER 5 Sheets-Sheet 5 Filed March 27, 1952 INENTOR.
fiiiifoelvzx United States Patent CONTINUOUS AUTOMATIC FLEXIBLE CONVEYER Clifford H. Snyder, Dormont, Pa., assignor to The Colmol Company, New Lexington, Ohio, acorporation of Ohio Application March 27, 1952, Serial No. 278,940
2 Claims. (Cl. 198-92) This invention relates generally to conveyers and more particularly to a conveyer system supported on a flexibly coupled train of self-contained vehicular units attached to a mining machine to receive and convey material therefrom, and wherein each successive unit of the moving train is steered at the same relative-position that the mining machine changed its course and the units of the train thus follow in the same path.
It has been common practice to use shuttle cars and shuttle trains to transfer coal in tracltless coal mines. The principle involved in both instances requires the loading, the hauling, and the unloading of the shuttle device, which is required whether theshuttle device is a simple car,- or a train of cars. The shuttle train may be loaded at one end and unloaded at the other end; It may be steeredas a train from either end. The answer to the problem of steering and propelling a tracltless.
train comprising a consecutive series of fouror twowheeled vehicles, has been suggested by the use of several different structures.
None of these former structures will operate satisfactorily'for removing material suchas'coal from a continuous mining'machine. The greatest difiiculty'is that the continuous mining machine has to be stopped to permit the shuttle device to carry its load away from the continuous mining machine and another shuttle device to take its place. production of coal. The interruptioncaused by changing shuttle devices produces additional problems in the continuous mining machine operation, as well as presenting problems in haulage space and-spillage.
The principal object is the provision of a conveying train that avoids these difficulties by attaching the conveyer train to the continuous mining machine while being used so that the guiding and operation of themining machine guides and operates the conveyer train.
To operate continuously, the mining machine and conveyer train must be supplemented by a main haulageor conveying system, the loading portion of which may extend for substantially the full length of the train. Such a main haulage system may be a continuously moving belt, a pneumatic system or a second. or repeated conveyer train that extends to a tipple or other receiving device and capable of continuously handling, the coal. The receiving device such as this-must be capable of being readily extended into the mine as the mining progresses.
The mining machine cuts entries and rooms laterally from a main haul or entry which has a material receiving device, such as a belt conveyer. Break-throughs are then cut to interconnect the entries and rooms as the mining progresses in the ordinary manner. The intermediate conveyer train trails the mining machine through th circuitous path in progressively mining.
If it is necessary to withdraw from one room or entry to form the next consecutive room or entry, the whole of the train, and the mining machine, may be reversed as a unit, or the conveyer train mechanism may. be re- Suchstoppage materially reduces they Patented Jan. 1, 1957 structures may be adapted for the purpose of supporting this invention.
Other objects and advantages appear hereinafter in the following description and claims.
The accompanying drawings show for the purpose of exemplification without limiting the invention or claims thereto, certain practical embodiments of the invention, wherein:
Fig. l is a plan viewof a continuous mining machine having a train of two-wheeled vehicular cars supporting a single drag conveyer.
Fig. 2 is an enlarged view of an intermediate portion of the-conveyer shown in Fig. 1.
Fig. 3' is an enlarged view illustrating the portion of a conveyer train having a single belt conveyer.
Fig. 4 is a view of the structure shown in Fig. 3 at a corner.
Fig. 5- is an enlarged plan view'of a roller bumper for use on a corner in a mine.
Fig. 6 is a view in side elevation of the structure shown in Fig. 5.
Fig; 7 is a view inside elevation of a corner bumper structure engaging a portion-of aconveyer train.
Fig. 8 is a plan view of the tender side of a conveyer train made up of a series of four steerable wheel vehicular structures and employing an endless belt conveyer.
Fig. 9 is a plan view of the receiving unit of another form of vehicular conveyer train.
Fig. 10* is a plan view of the under side of an intermediate unit of the conveyer train for the receiver of Fig. 9.
Fig. 11 is a view in sideelevation of the structure shown in Fig. 9.
Fig. 12 is asectional view showing the junction of two vehicular sections. of the conveyer train units of Figs. 9 and 10.
Fig. 13-is.a side view in elevation of the discharge unit of the conveyer train.
Fig-.14 is a plan View of the discharge unit shown in Fig. 13-.
Fig. 15 is an enclosed sectional view taken in the line 15-15-of- Fig. 14'. a
A mining operation is illustrated diagrammatically in Fig. l, wherein 1 indicates the mining machine, which is mining in a secondary entry, and a conveyer train 2 extends therefrom to a position in the main entry in whichis installeda belt conveyer such as illustrated at 3.
The conveyer train. Zis provided with a receiving end 4, conveyer train traction means as indicated at 5, and the discharge end- 6 having a traction means 7, and an articulated boom 8 for directing the material from theendless conveyer 10, to the endless conveyer 3, from whence it is conveyed in the direction as indicated by the arrow to the tipple of the mine.
The conveyer train 2 is made upof receiving and discharge members 4-and 6-with traction means andeither of which can guide and draw the conveyer train through the mine, independently of the mining machine 1, however, the receiving structure 4 is attached to the mining machine 1, and when the latter is operated to move forward, the samecontrol functions to actuate the traction members Sand 7 to move the conveyer forward as a unit.
Although the conveyer train trails the mining machine, it may be made to supply it own propulsion energy, and is provided with motors for this purpose.
The intermediate sections of the conveyer train 2 are comprised of two-wheeled vehicles pivoted intermediate of their ends to each other, as indicated at 11, and these vehicular members are provided with the frame which supports a flexible structure such as illustrated at 12, which is a double deck member arranged to carry an endless drag conveyer such as illustrated at 13 in Figs. 1 and 2. This endless drag chain conveyer extends from the forward end of the conveyer train, being positioned-underneath the conveyer 13' of the mining machine and to receive the coal and transport the same between the flexible sides to the rear of the train and over the swinging beam 8 where it is finally deposited onto the endless belt conveyer, 3. 4
The two-wheeled vehicular units of the conveyer train may not exactly follow the previous car when being trailed, and may be required to have some form of bumper means on the corners of themine, to maintain the cars in proper alignment. Such a bumper structure is illustrated at 14 in Fig. l, and is also on the corners, as illustrated at 15 in Figs. 6 and 7, which have a series of vertical shafts 16 for rotatably supporting the pulleys 17 of which five are shown. The support 15 is placed on the floor of the mine, and is held in place by'the roof jacks, such as illustrated at 18. The roof jacks may be vertical or they may be disposed at an angle, such as indicated by the dotted line 19.
The pulleys 17 may engage the cable member 20 such as illustrated in Fig. 1, which is on the sides of the conveyer train, and which are supported by spaced eyes on the outer ends of the brackets indicated at 21 in Fig. l. The cable 20 will engage the pulleys and prevent the wheels from hampering the progress of the conveyer train.
In the structure shown in Fig. 2, the cable 20 is woven 7 between the pulleys rotatably carried by the vehicular structures as indicated. The cable 20 is held by the pulleys 22 on both sides of the vehicular wheels 23 and in back of the pulleys 24 which are intermediate of the vehicular wheels 23. In this way, the cars of the trains maintain their spaced position regardless of the articulated angle that the conveyer train must pass in following its path. The cable 20, together with the pulleys 22 and 24 engage the pulleys 17 on the center of guide posts at the corners of the mine for the purpose of aiding the movement of the conveyer train through its circuitous path in the mine.
In the structure as shown in Fig. 3, the cable member 20 has been replaced by the frame 25 that completely surrounds the vehicular member and is cut away adjacent the pivotal point between the vehicular members so that they may negotiate a curve such as illustrated in Fig. 4. The sides of the conveyer trough 26 of this structure, are flexible and are likewise made as a double deck so as to receive the upper and lower flights in this conveyer such as indicated at 27.
Referring now to Fig. 8 which shows the underside of a conveyer train made up of a series of four steerable wheeled vehicle structures, and which comprises the car units 30 having the axial members 31 on which is mounted the steerable wheel 32. The arms 33 of the steerable wheels are connected by the rod 34 to the pivoted tongue 35. The pivoted tongue 35 has a vertically movable extension bar 36 which is pivotally supported by the pin 37, to the tongue member 35, that is pivoted on the axle, as indicated at 38.
Each of the steering mechanisms and each of the units are identical, and one of each pair of wheels is provided with an arm 40 which is connected by the adjustable reach rod or steering rod 41. The cars may thus be independently steered by the preceding car. Since the extension member bar 36 is non-flexible, and has a vertical pivot connecting it with each of the ends to pivoted tongue members 35, when the first car is caused to deviate laterally by reason of the extension 36 being pulled in the direction of the deviation, the wheels are caused to turn, and the turning of the Wheels likewise turns the rear wheels. At this time, the body begins to turn and follow the previous car. However, since the body is turning, and the wheels have likewise turned relative thereto, the next succeeding extension bar 36 has not been effected to turn the front Wheels in the next succeeding car until they have arrived at the same position as that of the rear wheels of the previous car. This occurs when the body of the previous car has completely followed its lateral path, and wheels, let us assume, are again parallel with the body. Under these conditions, the tongue of the next succeeding car is swerved in the same lateral direction, at which time, the body starts to follow the same devious path, and produces the same effect on the rear wheels of that car. Similar structures of this character are shown in the prior art as previously mentioned.
The bodies 30 of the cars of this train are overlapped, and each is arranged to support an endless belt conveyer, and is provided with a motor for producing the propulsion of the train and a drive for the conveyer. A detailed structure of this character is disclosed in the following drawmgs.
Referring now to Fig. 9, wherein is shown the understructure of the intermediate car of a train of cars, the steering of which is somewhat similar to the structure as shown in Fig. 8, but in greater detail, and the receiving unit of this train includes a rather low, generally horizontal elongated main frame 40 which is fabricated from longitudinally, transversely and angularly extending channels, angles, plates, and the like, all welded or otherwise attached rigidly together. Adjacent its receiving end, the main frame 40 is constructed to form a hopper 41 which is adapted to receive material, such as coal, which discharges over the discharge boom of the associated mining machine, such as a continuous mining machine 1 or a loader. The hopper 41 preferably has a wide open bottom which is normally closed by the receiving end of the load carrying run of a continuous rubber fabric belt. The somewhat similar conveyer belt for the intermediate unit is illustrated in Figs. 10 and 11 of the drawings. The lateral sides of the bottom of the hopper 41 are provided with longitudinally extending strips 43 of rubber belting, or the like, which overlap the receiving belt an appreciable amount so as to reduce spillage of material from the hopper to a minimum.
The endless rubber belt 44 which conveys material such as coal, from one end of the frame 40 to the other, and discharges it into the receiving end of the following intermediate unit of the system, extends from a tail pulley 45 over hopper idler 46 and a plurality of troughing idlers 47 placed at longitudinally spaced positions along the frame 40'to a head or discharge pulley 48. The return run of the belt 44 extends rearwardly from the head pulley 48 around an adjustable take-up and bend pulley 49 thence forwardly around a drive pulley 50, thence rearwardly over return idlers 51 spaced at appropriate intervals longitudinally along the frame 40.
The drive pulley 50 is driven from an electric motor 52 which is mounted adjacent one side of the main frame 40 and preferably laterally outside the adjacent main longitudinally extending frame member thereof. Motor 52 is connected to the drive pulley 50 through a speed reducer 53 and appropriate chain and sprocket drive mechanism 54.
Adjacent one side and generally at the center of the main frame 40 there is an operators station at which there is a control box 55 for controlling the motor 52, as well as also simultaneously controlling all the conveyer belt motors of the entire system. There is an auxiliary control box which may be extended to the associated mining machine so that starting and stopping of the v conveyer belts of the intermediate system may be there controlled. 4
Adjacent the receiving end the receiving unit is provided with a hitch 57 which is pivotally attached to the frame of the associated mining machine 1 by a bracket 58 and a transversely extending horizontal pivot pin 59 about a transverse horizontal axis relative to the associated mining machine 60; the hitch otherwise being held against movement relative thereto.
The hitch 57 is provided with a universal joint 61 which is in general alignment with the longitudinal center line or axis of the main frame 40. As a consequence of this connection, the forward end of the hitch 57 is connected by a universal joint to the tongue 62.
The conveyer unit 40 is provided with two pairs of supporting and steering wheels at each end thereof. As clearly illustrated in the drawings, each pair of wheels designated at 66 preferably includes pneumatic tires. The wheels 66 are mounted for steering and are mounted on individual king pins for steering adjustment the king pins being carried on brackets rigidly attached to the frame.
The wheels 66 are steerable, and to this end they are provided with the usual steering mechanism 73, best illustrated in Fig. 9 of the drawings, which steering mechanism includes a conventional manually operable steering wheel 74.
In Fig. 9 of the drawings there is illustrated, among other things, the manner in which the receiver or two units of the conveyer system are mechanically coupled together for articulated movement relative to each other, particularly about an upright axis along their center lines. The connection also provides a limited amount of universal movement between two interconnected'units. The main frame 40 includes a V-shaped top cross-pieces}, the apex of which is substantially at the longitudinal center of the unit. This-cross-piece 83' is provided adjacent said apex, with at least a portion of the universal joint type connection similar to that hereinafter described in connection with Fig.9.
Eachintermediate unit includes a main frame 84 constructed similarly to the receiving unit. As shown in Figs. and 11, the frame forms a shallow receiving hopper 85 which is adapted to receive the material di'scharged over the pulley 48 of the receiving unit 40. The two sides of the hopper 85 are provided with a-flexible material guide 86 preferably made of rubber belting, or the like, which guides the material into the upper or load carrying run of an endless rubber belt 87 carried by the unit 84, and extending from the tail pulley 83-to thehead pulley 89. The upper or load carrying run of saidbelt 87 is supported by a plurality of longitudinally spaced troughing idlers 90-. There is also a material supporting idler 91 for supporting the upper run of the belt 87 adjacent the hopper 85.
ing controlled by the preceding unit, whether it be a receiving unit, or intermediate unit, and in turn passing the steering control onto the succeeding intermediate or discharge unit, as the case may be.
On each unit of the train, there is a pair of power driven and traction steerable wheels 98, each preferably including a pneumatic tire. The wheels 98 are mounted upon king pins for steering adjustment but are held against up'and down movement relative to the main frame 84. To provide the power or traction drive to the two wheels 98, a traction electric motor 99 is carried on one 6 side of one of the upright frame members of frame 84 and extends to a speed'reducer 100.
As best illustrated in Fig. 11 of the drawings,- a drive shaft 101 extends from the speed reducer 100 both upwardly and downwardly, said drive shaft 101 carrying a drive sprocket of a chain and sprocket drive 102-, which drives a vertical shaft 103, which in turn drives a bevel gear 104 meshing with a bevel gear 105 rigid with one of the wheels 98. The lower end of the shaft 101 is provided with a bevel gear 106, which meshes with another bevel gear 197, which drives a cross shaft 108 provided with appropriate universal joints. The cross shaft 108 drives an upstanding "shaft 109 through appropriate spur gears, which shaft 109 is provided at its upper end with a chain and sprocket drive 110 which in turn drives the other wheel 98 through mechanism which is substantially duplicated with that just described in connection with the first wheel 98.
pin, or to receive a portion bar 113 of a telescoping hitch which is used to interconnect two adjacent intermediate Lmits or to connect an intermediate unit and the receiving or discharge unit.
Units 40 and 84 are supported by a pair of independently spring-suspended wheels 114 preferably provided with pneumatic tires and mounted for steering a'djustment in a more or less conventional manner. The suspension mechanism for each of the wheels 114 includes a pivoted arm 1:15 pivoted at its inner end to a ce'nter casting 116 constituting a rigid part of the main frame 84.- The outer end of the arm 115 carries the king pin and axle bracket for the wheel.
Extending through a bifurcated portion of each pivoted arm 115 and through a wing of the casting 116' is an individual elongated torsion rod 117 which adjacent its forward end is splined to a keeper arm 118 which is bolted to the pivoted arm 115. It is evident that each torsion rod 117 provides a pivotal connection between a wheel supporting arm 115 and the center casting 11.6 of the main frame 84. Each of the torsion rods 117 extends rearwardly to the rear cross axle, upon which the rear wheels 98 are supported and is splined to a keeper arm 119 bolted to said rear axle. The torsion rods 117 extend through appropriate holes in said rear axle adjacent their splined connection to' the keeper arms 119 shown in Fig. 10.
The front wheels 114 are provided with steering link mechanism 120' generally similar to the steering link mechanism 111, includir'1g a bracket or tongue casting 121 which is preferably a duplicate of the tongue casting 112. The two steering link mechanisms 111 and 120 are preferably coupled together by steering link mechanism 122, said link mechanism 122 causing the wheels 114 to turn oppositely from the wheels 98.
Adjacent the front end of the unit, there is a hitch element 123 which is pivotally attached to the bracket or casting 121, and which is complementary to the hitch element 113 and cooperates therewith to extend the steering control from the receiving unit, as above described, through each intermediate unit and ultimately to the discharge unit.
Adjacent its rear end the intermediate unit is provided with a V-type cross piece 124 and adjacent its front end there is a generally similar V-type cross-piece 125. The cross-pieces 124- an'd 125 are complementary, as hereinafter described, to a similar pair of connecting members in connection-with an intermediate and discharge unit end of the first intermediate unit and the cross-piece or bracket 124 of the second intermediate unit, if present, or if not present, between the bracket 125 or the intermediate unit and a similar bracket, hereinafter described at the rear of the discharge unit.
From the description, it is to be noted that each of the units have four wheels and are power driven, and thus constitute at least part of the traction means for the complete conveyer system and is provided with mechanism whereby all of the supporting Wheels are steerable, the steering being controlled automatically normally by the receiving unit when going forward or on the alternative by the discharge unit when going backward, or as hereinafter described, by the discharge unit.
Attention is now directed particularly to Figs. 13 and 14 and to the construction of the discharge unit. Except for such differences as are obvious, or are pointed out, it is to be understood that the discharge unit is similar to the intermediate unit just described. Without going into too much detail, it may be stated that said discharge unit includes a main frame, 126. The main frame is supported upon pairs of front and rear interconnected steerable wheels which are attached by the illustrated hitch to the preceding intermediate unit. Said discharge unit is provided with an endless conveyor belt 127, driven by an electric motor 128. The driving roller, supporting idlers, and other elements of the discharge unit are essentially similar to those of the intermediate unit. It will be noted however, that, unlike the intermediate unit, none of the wheels of the discharge unit is power driven. Likewise, unlike the intermediate unit, there is a manual steering control cylinder 129 associated with the interlocking steering mechanism which may be controlled by one of the valves of a bank of hydraulic valves 130 which control various hydraulic motors of the discharge section, as hereinafter described more completely. As illustrated in Figs. 10 and 12 of the drawings, the bank of valves 130 is provided with a plurality of control rods and levers, whereby each valve may be operated from either side of the unit.
The discharge unit also carries an electric motor 131 driving a hydraulic pump 132 for providing hydraulic fluid to actuate the several adjusting motors on said dis charge unit. The discharge unit does not have any torsion rods comparable with the rods 117 of the intermediate unit, but the wheels are mounted for vertical adjustment by mechanism quite similar to that provided 7 for the intermediate unit. Said wheels, however, are
vertically adjustable about their inward pivot points by means of a double acting hydraulic piston motor 133. The piston rod and cylinder of said motor 133 are connected to opposite ends of the wheel arms as clearly illustrated in Fig. of the drawings.
Adjacent the end of the main frame 126, the discharge unit is provided with a cross-piece 134 which is comparable in structure with the cross-piece 125 of the intermediate section. Extending forwardly from the front of the discharge unit and forming a part thereof is a discharge boom 135 which is formed in two sections namely, the rear receiving section 136 and a front discharge section 137.
As best illustrated in Figs. 13 and 14 of the drawings, the entire discharge boom 135 is mounted for swinging movement about an upright axis relative to the front portion of the body proper of the discharge unit. This swinging connection is provided by top pivot means 138 which pivotally connects the aforementioned crosspiece 134 and a cross-piece 139 forming part of the frame of the rear portion 136 of the boom 135. Adjacent the bottom of the frame of the receiving section 136 there is also a pivot connection which is in alignment with the pivot connection 138. These pivot means provide for swinging movement of the entire boom 135 about an upright axis along the longitudinal center line of the discharge unit.
Mounted on the two sections 136 and 137 of the boom 135, there is an endless belt 141 which travels over appropriate tail, head, bend, and drive pulleys, and is supported by appropriate idlers, all as clearly illustrated in Figs. 13 and 14, of the drawings. The belt 141 will receive material from the belt 127, and dis-. charge it over the head pulley of the boom onto a receiving belt conveyer or any other receptacle, or merely onto the ground.
The receiving section 136 of the boom 135 carries an electric motor 142 which drives the drive pulley thereof through appropriate drive mechanism illustrated particularly in Fig. 13 of the drawings. The discharge section 137 of the discharge boom 135 is mounted for adjustment on a transverse horizontal axis provided by pivot means 143, this adjustment being controlled by a double acting hydraulic piston motor 145, the cylinder of which is pivoted to the main frame 126, and the piston of which is pivotally attached to an operating arm carried by the frame of the receiving section 136 of the discharge boom 135.
The various hydraulic motors of the discharge unit, including the steering motor 129, Fig. 10, the wheel adjusting motor 133, Fig. 13, the boom swinging motor 145, and the motor for adjusting the discharge section 137 of the boom 135 are controlled by individual lines to the hydraulic valves 130. All of these cylinders are double acting and are locked in their normal positions of adjustment. The valve which controls cylinder 129 also has a fourth position in which this cylinder is allowed to float freely. This is required, of course, when the steering of the discharge unit is controlled by the adjacent intermediate unit.
The discharge end of the discharge unit may be raised and lowered by controlling the motor 133. In addition, the final discharge pulley, namely, the discharge pulley of the discharge section 137 of the discharge boom 135, may be raised and lowered by the cylinder 144.
Attention is now directed particularly to Fig. 12 of the drawings where there is illustrated in some detail the overlapping of any two adjacent units, which may be either the receiving and the intermediate units, the intermediate units themselves, or an intermediate unit and the discharge unit. In the particular illustration, the last intermediate unit is shown discharging into the discharge unit.
As clearly illustrated, the belt 87 of the intermediate unit overlaps the belt 127 of the discharge unit. It is therefore obvious that material being conveyed, such as coal, will drop a relatively short distance from the belt 87 and be received by the belt 127 and carried on to be received by the discharge boom belt 141 from which it will be discharged into a receiving room conveyer, or the like.
The main frames of the intermediate and discharge units are connected together by means of a ball and socket joint or connection 146 which interconnects the cross-piece of the main frame 84 of the intermediate unit with a similar cross-piece 147 at the rear and top of the unit 126. The ball and socket connection 146 provides articulated or free swinging movement between the two conveying units on an upright axis, and in addition, it provides for limited movement between said two units on horizontal axes. In other words, it is a limited universal joint connection. The steering control is transferred from the intermediate unit to the discharge unit by means of the hitch 123, 113, which two telescoping parts provide for relative longitudinal movement between the two units.
The length of the conveyor system may be adjusted at will by controlling the number of intermediate units.
The mining machine 1 may have a conveyor train attached to it which follows it over a circuitous path through the various entries, break-throughs, and rooms, receiving the output from the mining machine, and delivering it over the discharge boom 135 onto a main entry or receiving conveyer 3 which may, for example, be an endless belt conveyer in the main haulage entry of the mine, as shown in Fig. 1.
The discharge boom may swing laterally to discharge the material onto the conveyer 3. The conveyer system follows along the receiving conveyer and is parallel therewith for a significant distance, then winds through a break-through, continuing to the rear end of the mining machine 1. It is evident that the mining machine can proceed in any direction to an appreciable distance from the position illustrated before it will be impossible for the discharge boom 135 to discharge the coal onto the receiving conveyer 3. When that condition is realized, it is usually necessary to extend the receiving conveyer 3.
By virtue of this important link between the continuous mining machine and the main entry or receiving conveyer 3 it is possible for the mining machine 1 to operate in a continuous manner substantially without stopping. Furthermore, it is entirely practical for the mining machine to back up as the traction motors for the intermediate conveyers are reversible and are all controlled from a central control station.
Those skilled in the art may make various changes in the details and arrangements of parts without departing from the spirit and scope of the invention as defined by the claims hereto appended, and applicant therefore wishes not to be restricted to the precise construction herein disclosed.
Having thus described and shown an embodiment of 10 the invention, what it is desired to secure by Letters Patent of the United States is:
1. A flexible conveyor having at least three tandem conveyor supporting units, including a receiving unit, a discharge unit, and at least one intermediate unit, supporting wheel means mounted for steering at opposite ends of each of said units, steering means between the cooperating ends of said units in the form of a tongue pivoted on a vertical axis to each cooperating end of each unit, bar means pivoted at its ends on horizontal axes to the tongues of adjacent units, steering rod means pivotally connecting each tongue of each unit with the adjacent supporting wheel means of each unit, a steering rod coupling means interconnecting the supporting wheel means at opposite ends of each unit for steering said last mentioned wheel means in unison when a prior conveyor unit deviates laterally from a path of travel and its tongue actuates the adjacent tongue of the following unit.
2. The structure of claim 1 which also includes control steering means on each end unit to steer the wheels of said end unit in traveling the flexible conveyor in opposite directions.
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488,041 Great Britain June 20, 1938 370,224 Italy Apr. 11, 1939 611,784 Great Britain Nov. 3, 1948