US3113762A

US3113762A - Mining machine having a reciprocating cutter

Info

Publication number: US3113762A
Application number: US5857A
Authority: US
Inventors: Herrmann Julius
Original assignee: Gewerkschaft Eisenhutte Westfalia GmbH
Current assignee: Gewerkschaft Eisenhutte Westfalia GmbH
Priority date: 1959-02-04
Filing date: 1960-02-01
Publication date: 1963-12-10
Anticipated expiration: 1980-12-10

Description

MINING MACHINE HAVING A RECIPROCATING CUTTER Filed Feb. 1, 1960 J. HERRMANN Dec. 10, 1963 2 Sheets-Sheet 1 IN VE N TOR $12111: Herr/ha. rm

2 Sheets-Sheet 2 J. HERRMANN Dec. 10, 1963 MINING MACHINE HAVING A RECIPROCATING CUTTER Filed Feb. 1. 1960 INVENTOR Julius Herrmann BY W W M United States Patent 3,113,7 62 MENHNG MACHENE HAVING A R'ECIPRQCATING CUTTER Julius Hcrrmann, Altlunen, Germany, assignor to Gewerkschaft Eisenhutte, Wethrnar, near Lunen,

Westphalia, Germany, a corporation of Germany Filed Feb. 1, 1969, Ser. No. 5,857 Clmms priority, appiication Germany Feb. 4, 1959 17 Claims. (Cl. 26213) The present invention relates to a machine for mining coal, minerals, and the like, having cutting means for loosening the material to be extracted from the mine face, and more particularly the invention relates to such a machine which may be moved in a longitudinal direction with respect to the mine face to be worked which includes a base frame and a carrier for the cutting means, said carrier being slidably mounted on the frame for relative back and forth movement with respect thereto in longitudinal direction. Cushioning means are additionally provided inter-connecting the carrier to the frame.

In connection with the mining of coal, minerals, and the like, through mine face extraction in underground minin operations, for example, those machines have attained great significance which are used for this purpose wherein the machines are guidably positioned for back and forth movement along the mine face to be worked and include cutting or loosening tools effective for loosening the material for the mine face in at least one direction of movement of the machine. These machines are suitably provided with an endless, traction mechanism such as an endless chain mounted for movement on two spaced guide wheels and having the mining machine secured to the chain for movement therewith. Generally, the mining machine is driven by the endless traction mechanism along a path parallel to the mine face for the loosening of the coal or other minerals to be extracted, and the extracted coal is removed from the site by means of a conventional conveyor device, such as a double chain scraper-conveyor positioned parallel to the path of movement of the mining machine. The mining operation may be increased in efficiency by the application of various kinds of loosening or cutting tools mounted on such machines.

It is an object of the present invention to provide an improved mining machine of the foregoing kind, having a cuttim or loosening tool carrier displaceably and preferably slidably positioned along the longitudinal side of the machine frame which is adapted to face the mine wall to be worked.

It is a further object of the invention to provide such a mining machine in which the carrier is mounted on the machine frame by cushioning means and said carrier and cutting or loosening tools are driven back and forth in longitudinal direction by means of a driving mechanism capable of producing oscillations of comparatively high frequency for working said cutting tools into the mine face.

Other and further objects of the invention will become apparent from a study of the within specification and accompanying drawings in which,

FIGURE 1 is a side elevation of a mining machine in accordance with the invention having cutting means protime Patented Dec. 10, 1963 vided on either end thereof on the side remote from view;

FIGURE 2 is an end view of a mining machine in ac cordance with the embodiment of FIGURE 1, illustrating the application of the same to a mining face to be worked, and

FIGURE 3 is a top view, partially in section, diagrammatically illustrating details of construction of the mining machine in accordance with the invention.

FIG. 4 is an enlarged schematic sectional view of a portion of FIG. 3 showing more clearly various details of construction.

It has been found, in accordance with the present invention that a machine for mining coal, minerals, and the like, may be provided which is adapted to be moved along a mine face to be worked and which has cutting means for loosening the material to be extracted. The mining machine accordingly comprises a. base frame and a carrier mounted on the frame for relative back and forth movement with respect to the frame in a longitudinal direction. Cutting means are provided on the can rier and preferably at either end thereof so that as the carrier moves back and forth, the cutting means or tools may be worked into the coal or other mineral whereby to loosen the same. The carrier is mounted on the frame by means of a cushioning construction inter-connecting the carrier to the frame and permitting the carrier to be cushioningly displaced longitudinally with respect to the frame. Driving means are provided for oscillating the carrier, and, in turn, the cutting tools back and forth with respect to the machine frame.

During normal use conventional machines, provided with cutting tools, have been beset with certain problems among which is the working loose and sliding off of the cutting tools from their seating connections due to the force and vibration of the mining machine and impact with the mine face. In accordance with the present invention, nevertheless, by utilizing a short-stroke, rapid, back and forth movement of the cutting tool carrier by suitable driving means, any loosening or sliding off of the cutting tools is avoided as well as any consequent tilting or swaying movement of the entire mining ma chine occasioned thereby. In accordance with the rapid oscillating movement of the carrier with respect to the machine frame, a considerable kinetic energy is made available which enables the loosening or cutting tools to strike the coal to be extracted with great impact during the back and forth movement of the cutting tool carrierv By means of the cushioning connection between the carrier and frame of the mining machine in accordance with the invention, the longitudinal oscillating movements of the cutting tool carrier are dampened whereby mechanical losses are reduced to a minimum and accordingly wear and tear on the moving parts.

Specifically, to effect a reduction in mechanical losses and permit a disturbance-free functioning of the mining machine, the cutting tool carrier mounted for displace-- ment back and forth with respect to the machine frame is provided with cushioning means therewithin for exerting this dampening effect. The cushioning means may include spring elements acting in the direction of movement of the cutting tool carrier which abut, on the one hand the stationary machine frame, and on the other hand, the displaceably moving cutting tool carrier. The

6! employment of such mechanical cushioning elements permits the desired dampening effect to be attained with a minimum of production cost and a minimum of upkeep.

Thus, in order to obtain a high degree of mechanical effectiveness, in accordance with the invention, the cushioning means, including the spring elements, are situated for coaction in coincidence with the direction of movement of the cutting tool carrier and preferably passing through the center of gravity of the cutting tool carrier. In this manner, the carrier may be accelerated and retarded in its rapid, oscillating movement, free from the influence of excessive momentum along its level of motion.

The driving means used in accordance with the invention is one which is capable of producing essentially longitudinal oscillations of the cutting tool carrier at a substantially rapid rate. The driving means is preferably stationarily positioned within the machine frame and through suitable linkages translates rotary motion, for example, into oscillating motion for driving the carrier.

Thus, the driving means may include an electric motor or any engine capable of producing rotational movement, such as a compressed air motor of conventional design. Advantageously, the motor is connected to a drive shaft via a suitable flexible linkage or coupling and the drive shaft, in turn, is connected through transmission means with a crank shaft rotatably mounted on the frame and having a cam end portion. Notably the cam end portion of the crank shaft extends from the machine frame into the carrier and coacts with a slide bearing, linkably or pivotably connected to the carrier. By rotation of the cam end portion of the crank shaft, the slide bearing 'is caused to move back and forth, in turn moving the carrier to which it is connected. The cutting tools mount ed on the carrier are accordingly oscillated back and forth a double chain scraper conveyor of conventional design.

Since the conveyor is provided immediately next to the mining machine, along a path parallel to the mining face to be worked, the conveyor apparatus serves as a convenient guiding surface for the flat extensions of the machine frame so as to prevent an upsetting of the machine or a turning of the same out of the normal longitudinal path of travel as a consequence, for example, of excessive counterforces acting upon the cutting tools.

Referring to the drawings, a mining machine frame 1 is shown for the extraction of coal or other minerals, such as is used in underground mining operations. The mining machine frame 1 is adapted to be positioned approximately parallel to the coal face 2 to be worked, the conveyor 3 for removal of the coal from the extraction site, adjacent thereto, additionally serving as a parallel guide for the moving machine frame. 1. The mining machine frame 1 is mounted for movement within a long wall or stay 4 of the minewand along the coal face 2. by any suitable means such as a pull chain 7, attached at either end of the mining machine frame via terminal links 5 and 6. Each end of the chain 7 may be suitably driven for movement of the machine frame 1 in longitudinal direction with respect to the mine face 2, for example, by means of a winch (not shown) maintained at a suitable distance from the area being worked. Generally, the chain 7, when connected to the mining machine frame 1, defines an enless chain mounted on a winch at a suitable distance from each end of the mining machine frame 1, the upper or return portion of the chain passing through guide tubes 8 and 9 situated on the top of the machine. By the use of suitable driving power, the winches may be rotated in cooperation with A; one another to draw the chain and, in turn, the machine along the mine stay 4 in the usual member.

, these cutters are guided back and forth along the coal face 2 within the stay '4, accordingly, a coal strip 20 of the coal bed is loosened and extracted. The thickness of strip 24) varies depending upon the distance and depth of penetration of the cutters as well as the distance the chain '7 is maintained with respect to the coal face 2.

Cutters 16 to 14' and 15 to 19 are detachably fasttened to an elongated tool carrier 23 at either end there of against transverse faces 21 and 22 via tongue and groove-connections 24 and 25a respectively. Screws or bolts (not shown) are used to effect the detachable connection of the cutters to the tool carrier 23 Tool carrier 23 is displaceably and preferably slidably seated longitudinally along the rear side of the machine frame 1 to that carrier 23 is immediately adjacent the mine face 2 during normal operations. Thus, where a vertical mine face 2 is to be extracted, the rear wall of machine frame 1 contains the vertically mounted carrier 23 along its rear side as may be seen from FIGURE 2. Thus, carrier 23 may be displaced in longitudinal direction, along a path parallel to the mine face 2 and parallel to the path of movement of machine frame l in consequence of the movement of chain 7. Tool carrier 23 is cushioningly mounted on frame l and preferably resiliently corn nected to frame 1 for execution of longitudinal oscillating movements of comparatively high frequency with respect to frame 1, caused by a suitable driving means mounted on frame 1 for this purpose.

FIGURES 2 and 3 indicate clearly that the cutting tool carrier 23 is of box-shaped construction, having a rear side wall 25, and a forward side wall 26, positioned approximately parallel to and spaced from one another as well as end walls 21 and 22 transversely connecting walls 25 and 26. Tool carrier 23 is further reinforced by meansof

transverse cross pieces

27 and 28 as well as 2.9 and 30. End walls 21 and 22, as well as

cross pieces

27, 28, 29, and 30 are suitably bonded to side walls 25 and 26, as for example by welding.

Tool carrier 23 is provided, in a chamber formed by side walls 25 and 26 and transverse cross pieces .29 and 39, with suitable means for cushioning the back and forth movement of the tool carrier. This cushioning device includes in detail (see FIG. 4) a plurality of

plate springs

31, 32, arranged in a series, resiliently coacting with one another, and movable back and forth on guide tubes 33 and bilateral projection 34, telescopically interlocking at either end with guide tubes 33. Specifically,

guide sleeves

35 and 35 of guide tubes 33 slidably receive therewithin

guide bolt projections

37 and 38 respectively of bilateral projection 34 in coaxial arrangement. u d sleeve 35 is secured along its base portion to transverse cross piece 29 of tool carrier 23 while guide bolt projec tion 37 cooperating with guide sleeve 35, along its longit-udinal free end portion of reduced diameter is fastened at its opposite end to transverse clamp 39. On the opposite side, in the same way, guide bolt projection 38, with its free end longitudinally displaceably received within guide sleeve 36, is fastened at its other end to clamp 39. Guide sleeve 36 is fastened, in turn, to transverse cross piece 30 of tool carrier 23.

The guide means 33 and 34, for the plate springs, are positioned approximately parallel to the direction of movement of the tool carrier 23 so that plate springs: 31 and 32, which may be activated solely upon the ap. plication of pressure, are only effective to dampen the:

back and forth movement of the tool. carrier 23. Thus,

plate springs 31 and 32 react in'a resilient manner to cushion the oscillating movement of the carrier 23. Plate springs or disc springs 31 and 32 are provided in plural arrangement abutting at one end transverse cross piece 29 or 36, as the case may be, and at the other end, clamp 39. Clamp 39 is rigidly connected to support prop 4% which intersects tool carrier 23 approximately parallel to and in between transverse cross pieces 29 and Stl. Prop 411' is connected at its upper and lower ends to machine frame 1 in a rigid manner. Consequently, while guide means 34- is rigid with respect to frame '1 through the rigid connection between clamp 39' and prop 4 0, and in turn the rigid connection between prop 4G and frame 1, guide means 33, attached to oscillatable carrier 23, may be moved back and forth in telescopic asrangement with guide means 34 under the action of plate springs or disc springs 31 and 32.

If it is desired or necessary, one or more additional guide means 33 and 34 may be provided in approximately vertical arrangement, one above the other, including springs 31 and 3-2. in each instance, the guide means are arranged for attachment to support prop 40 with respect to the machine frame 1 and, on the other hand, for attachment with carrier 23. It will be appreciated that, in the alternative the guide sleeves may be provided as the rigid member connected to clamp 35, prop 4G, and machine frame 1 while the guide projections may be provided on carrier 23, i.e. the moving member.

As is evident from FIGURES 2 and 3, tool carrier 23 essentially extends across the rear side of machine frame 1 and is conducted in sliding engagement along the bottom wall 41 and along the top Wall 42 as Well as along the side walls 43 and id of machine frame 1. Retaining strips 45 and 45 are attached, as by Welding, to bottom wall 4-1 and top wall 4 respectively of the machine frame so as to overlap the rearmost face 25 of carrier 23 to a certain degree. Hence, retaining strip 45, in cooperation of bottom wall at, and retaining strip 46, in cooperation with top wall 22, define a longitudinally extending groove with side walls 43 and 44 within which carrier 23 is conveniently displaceably and slidably received for back and forth movement therealong.

A transverse plug 7, connecting walls 25 and 26 of carrier 23, is provided in a plane passing generally through the center of gravity of the carrier. Plug 47 is inter lockingly attached in place by rings 48 and 49 cooperating with corresponding grooves defined in the surface of plug 47. A slide bearing 50 is swivelingly or pivotally positioned on plug &7 and secured against axial displacement by means of retaining jaws 51 and 52, bolted together on either side thereof. laws 51 and 52 are spaced apart by means of slide rod 53 which surroundingly couples slide bearing so about its outside circumference. T he slide rod 53 extends in a direction towards transverse cross piece 27 of tool carrier 23 extending in surrounding engagement with a slide bearing 54 which is swivelingly seated for coaction with a flying crank cam 55 of a crank shaft 56. Slide bearing 54 is secured against axial displacement by means of jaws 5'7 and 58 in the same manner as slide bearing 512 is secured by means of jaws 51 and 52. law 57, additionally covers over the end of crank cam 55, jaws 57 and 513 being spaced apart by the presence of slide rod 53 therebetween in the same manner as jaws 51 and 52 are spaced apart. Crank shaft 56 extends approximately transversely to the longitudinal axis of the machine and in an approximately horizontal direction with respect thereto, where carrier 23 is considered in an upright or vertical position with respect to the work face and directional path of travel. Crank shaft 56 is suitably positioned within a transmission housing 59 fastened to the bottom portion of machine frame 1 by means of screws or rivets. Crank shaft 56 is suitably rotatably seated in slide bearings 60 and 61 of transmission housing 59. Provided on shaft 56, between bearinss s9 and 61 is a cone pinion or cone cog wheel 62 which cooperates with a further cone pinion or cog Wheel 63, positioned for rotational engagement therewith at right angles thereto. Cone pinion 63 is secured to the end of drive shaft 64 of the driving means transmission which is directed approximately horizontally with respect to the machine frame 1 and parallel to the path of movement of tool carrier 23. Shaft 64 is rotatably seated Within slide bearings 65 and 66 of the transmission housing 59. The opposite end of drive shaft 64 is coupled via a flexible coupling or linkage represented at 6'7 with the approximately coaxially arranged shaft 68 of motor 69 which is likewise fastened within machine frame 1. Motor 69 may be any suitable motor capable of supplying the drive energy required, such as an electric motor or a compressed air engine, receiving its electrical current or compressed air via an arm "ill positioned on the upper side &2 of frame 1.

Thus, motor 69 transmits power, via shaft 65%, flexible linkage 67, and suitably journaled drive shaft 64, to crank shaft 56 by means of the right angle cone pinion interacting arrangements 62 and 63 It will be appreciated as shaft 56 revolves at comparatively high speed a rapid frequency of oscillations are produced with respect to cam portion 55. As cam portion 55 .slidably revolves within slide bearing 54, the same is caused to oscillate back and forth, in turn transmitting these oscillations via slide rod 53 and slide bearing Sit to plug 47. Since plug 47 is rigidly connected to carrier 23, the carrier is moved back and forth in longitudinal direction in sliding engagement within the groove formed by bottom wall at, top wall 42;, retaining

strips

45, 46 and side walls 43, 44. Since carrier 23 is mounted via the cushioning arrangement, represented by plate springs 31 and 32, guide means 33 and 34, including

sleeves

35 and 35, as well as

projections

37 and 38, and clamp 39, to prop 49, carrier 23 may be vibrated or oscillated back and forth along its path of longitudinal travel forcing the cutting tools into the face 2 under extremely favorable conditions.

Side walls 43 and d4- of machine frame 1 extend approximately parallel to the coal face 2 and thus serve as efiicient guide surfaces for tool carrier 23. Nevertheless, the same are reinforced with the angular frames '71 and '72 respectively in cooperation with front wall 73. These members are secured, as for example by screws or bolts with the bottom wall 41 and top wall 4-2 for better reinforcement. Jaw clamps 74 and 75' are provided adjacent bottom wall 41 of machine frame 1 which serve to seat therebetween, in fixed arrangement, the terminal links 5 and 6 respectively of chain 7. Screws or other suitable means may be used to secure jaws 74 and 75 together in tight engagement.

An optimal feature in accordance with the invention is the provision for fiat projections '76 and 77 attached along a portion wall 41 and which extend below the entire Width of conveyor 3, serving as an additional guide and safety device to prevent tilting or movement of the machine outside of its normal path of travel.

As may be seen from FIGURE 2, the portion of the frame 1, at either end thereof, i.e. the part situated along the forward portion of frame 1, which may be placed in sliding, abutting engagement with the immediate side of conveyor 3, is suitably developed with replaceable stripping elements '78 for more efficient guiding engagement of frame 1 along its forward side with conveyor 3. Furthermore, a guiding strip '78), extending along a portion of the forward side of frame 1, parallel to the longitudinal direction of conveyor 3, is provided on frame 1 as a further guide for keeping the mining machine within its desired path of movement. Convey-or 3, of course, may be developed in any optional manner, such as, for example, as a conventional double-chain-scraper-conveyor.

In accordance with the present invention, motor 69, for example, may be an electric motor having a capacity of 33 kw. corresponding approximately to 40 horsepower. The gear ratio of the cone pinions, 62 and 63, of the transmission means is so chosen that the tool carrier 23 may be moved back and forth so as to execute approximately 1,200 double strokes per minute. The acceleration forces of the tool carrier 23, including the cutters 10- to 14 and 15 to 19, may approach, for example, approxi-- mately 8,000 kilograms. By providing the characteristic of plate springs 31 and 32 so as to conveniently correspond approximately to the acceleration forces provided for the tool carrier, the sum of the spring compressive forces of

spring arrangement

31 or 32 i.e. at equilibrium likewise will amount in each case to approximately 8,000 kilograms. The highest compressive force of an individual spring means i.e. under the acceleration forces of the tool carrier thereagainst amounts to about 11,000 kilograms so that in view of the foregoing a change in indi vidual spring compressive force of about 3,000 kilograms will exist. More specifically, upon movement of the carrier to the right, springs 31 are compressed beyond the normal 8,000 kilogram compression, i.e., up to 11,000 kilograms, while springs 32 are relaxed from the normal equilibrium 8,000 kilogram compression to a force of only 5,000 kilograms, representing a change in individual spring force of 3,000 kilograms although a difference of 6,000 kilograms will exist in the form of a vector force (ll,000-5,000) at the maximum displacement of the carrier. The now higher compressive force of springs 31 at the end of the carrier movement to the right will cause the return of carrier 23 towards the left until the point of equilibrium is again reached, whereupon the opposing 8,000 kilogram forces of each of springs 31 and springs 32 will be balanced once more. The further movement of carrier 23 to the left may now be effected by the driving force of crank pin 55 and connecting rod 53. During any idling phase of the operation, the bearing load on the crank drive is practically negligible, equaling almost zero, with the result that a great degree of mechanical efliciency is obtainable. Thus, the capacity of the motor may be almost completely and totally supplied to urge the cutting tools into the mine face, i.e. this capacity is converted almost completely into productive work. Accordingly, at approximately 1,200 thrusts of the cutter tools against the coal face, the kinetic energy available will amount to about 150 mkg. per thrust. Through this rapid back and forth movement of the cutters, the coal will be loosened from its solid arrangement and pushed, by means of the angular portions '71 and 72a outwardly and into conveyor =3.

While a chain has been shown to be used for conveying the mining machine, in accordance with the invention, along its longitudinal path of travel, any traction means, such as a cable, coupled with suitable traction means, may be used.

What is claimed is:

1. Machine for mining coal, minerals, and the like which is adapted to be guidably positioned for movement in a longitudinal direction with respect to the mine face to be worked and having cutting means for loosening the coal, minerals, and the like from the mine face as the machine is moved in longitudinal direction with the cutting means in cutting engagement with the mine face, which comprises a base frame, a cutting means carrier mounted on said frame for relative back and forth movement with respect to said frame in longitudinal direction, cutting means being provided on at least one end portion of said carrier for cutting engagement with the mine face, said carrier being mounted on said frame by a pair of opposed resilient cushioning means arranged in the carrier for coaction in coincidence with the direction of movement of said carrier, each'cushioning means being pro-stressed under compression between the carrier and the frame in the longitudinal direction and operatively inter-connecting said carrier to said frame for said back and forth movement, and oscillation imparting driving means separately mounted on said frame for rapidly moving said carrier back and forth and for urging said cutting means into cutting engagement with the mine face.

2. Machine'according to claim 1 wherein said carrier is slidably mounted on said frame.

3. Machine according to claim 1 wherein said cutting means are provided on each end portion of said carrier.

4. Machine according to claim 1 wherein said carrier is slidably mounted along the rear wall of the frame within groove means provided on said frame.

5. Machine according to claim 1 wherein said frame is provided with an endless chain means connected at each end portion of the frame, said chain means being mounted for movement in longitudinal direction with respect to the mine face to convey said machine therealong.

6. Machine according to claim 1 wherein the front wall of said frame is provided along its bottom portion with flat extensions projecting outwardly, said extensions being adapted to underlie a conveyor for the material extracted from the mine face situated longitudinally adjacent to the frame.

7. Machine according to claim 1 wherein said driving means moves said carrier back and forth in longitudinal oscillating movement at substantially high frequency.

8. Machineaccording to claim 1 wherein each said cushioning means includes at least one telescoping arrangement including a recess member connected to one of said frame and carrier and a projection member connected to the other, said projection member being slidably received within said recess member in a direction substantially parallel to the longitudinal movement of said carrier and a plurality of cooperating spring means operatively interposed between and engaging both said members under pro-stressed compression.

9. Machine according to claim 8 wherein said spring means are provided as a plurality of cooperating plate springs coaxially disposed on said recess member and said projection member and engaging said members under pre-stressecl compression.

10. Machine according 'to claim 8 wherein'cutting means are provided on each end portion of said carrier,

and the pair of opposed cushioning means together includes a common bilateral projection member having two opposed projection ends extending in the longitudinal direction, said bilateral projection member being disposed etween and slidaoly received atsaid projection ends in two separate correspondingly opposed recess members for relative movement therewith in a direction substantially parallel to the longitudinal movement of said carrier, a plurality of cooperating spring means being operatively interposed between and engaging under pre-stressed compression, each of such recess members, and the corresponding projection end thereat.

11. Machine according to claim 8 wherein said driving means is situated on said frame and a crank shaft is rotatably mounted on said frame connected for driving engagement by said driving means, said crank shaft being situated perpendicular to the direction of movement of said carrier and being provided with a flying crank cam end portion.

12. Machine according to claim 11 wherein said carrier is provided with a slide bearing element pivotably mounted thereon for movement therewith, said flying crank cam end portion rotatably engaging said slide bearing element to force the same, by means of said cam end portion, and in turn said carrier back and forth in longitudinal direction with respect to the mine face.

13. Machine according to claim 12 wherein said crank shaft and the drive shaft of said driving means are positioned at right angles to each other and are provided with cooperating cone pinionrneans for transmitting the rotational driving force of said driving means to said crank shaft.

14. Machine according to claim 13 wherein the drive shaft is connected to said driving means through a flexible coupling means.

15. Machine according to claim 8 wherein said spring means are prestressed spring discs which together have 9 a spring force characteristic corresponding approximately to the acceleration forces provided for movement of said carrier.

16. Machine according to claim 15 wherein the resultant direction of action of the spring discs and axis of movement of the carrier substantially coincide and pass through the point of application of the driving force of the driving means for urging the carrier back and forth.

17. Machine according to claim 16- wherein said resultant direction of action of the spring discs and said axis of movement of the carrier additionally pass through the center of gravity of the carrier.

References Cited in the file of this patent UNITED STATES PATENTS White June 21, 1938 Pearson et a1. Sept. 16, 1952 Vogel Mar. 2, 1954 Bainbridge Sept. 2 1954 Sloane Oct. 5, 1954 Herrmann May 15, 1956 FOREIGN PATENTS France Dec. 8, 1954 Great Britain Aug. 3, 1933 Germany Mar. 12, 1937

Claims

1. MACHINE FOR MINING COAL, MINERALS, AND THE LIKE WHICH IS ADAPTED TO BE GUIDABLY POSITIONED FOR MOVEMENT IN A LONGITUDINAL DIRECTION WITH RESPECT TO THE MINE FACE TO BE WORKED AND HAVING CUTTING MEANS FOR LOOSENING THE COAL, MINERALS, AND THE LIKE FROM THE MINE FACE AS THE MACHINE IS MOVED IN LONGITUDINAL DIRECTION WITH THE CUTTING MEANS IN CUTTING ENGAGEMENT WITH THE MINE FACE, WHICH COMPRISES A BASE FRAME, A CUTTING MEANS CARRIER MOUNTED ON SAID FRAME FOR RELATIVE BACK AND FORTH MOVEMENT WITH RESPECT TO SAID FRAME IN LONGITUDINAL DIRECTION, CUTTING MEANS BEING PROVIDED ON AT LEAST ONE END PORTION OF SAID CARRIER FOR CUTTING ENGAGEMENT WITH THE MINE FACE, SAID CARRIER BEING MOUNTED ON SAID FRAME BY A PAIR OF OPPOSED RESILIENT CUSHIONING MEANS ARRANGED IN THE CARRIER FOR COACTION IN COINCIDENCE WITH THE DIRECTION OF MOVEMENT OF SAID CARRIER, EACH CUSHIONING MEANS BEING PRE-STRESSED UNDER COMPRESSION BETWEEN THE CARRIER AND THE FRAME IN THE LONGITUDINAL DIRECTION AND OPERATIVELY INTER-CONNECTING SAID CARRIER TO SAID FRAME FOR SAID BACK AND FORTH MOVEMENT, AND OSCILLATION IMPARTING DRIVING MEANS SEPARATELY MOUNTED ON SAID FRAME FOR RAPIDLY MOVING SAID CARRIER BACK AND FORTH AND FOR URGING SAID CUTTING MEANS INTO CUTTING ENGAGEMENT WITH THE MINE FACE.