US 2659585 A
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Nov. 17. 1953 R. A. M CALLUM POWER DRIVE CONNECTION FOR COMBINED ROTATABLE AND OSCILLATABLE MINING TOOLS 4 Sheets-Sheet 1 Filed June 29, 1951 I7? vewfw 1 305 671% Kai/air? Nov. 17. 1953 R. A. M CALLUM POWER DRIVE CONNECTION FOR COMBINED ROTATABLE AND OSCILLATABLE MINING TOOLS 4 Sheets-Sheet 2 Filed June 29, 1951 F1, f E m Q w Nov. 17. 1953 R. A. M CALLUM POWER DRIVE CONNECTION FOR COMBINED ROTATABLE AND OSCILLATABLE MINING TOOLS 4 Sheets-Sheet 3 Filed June 29, 1951 mm mm Nov. 17. 1953 R. A. M CALLUM POWER DRIVE CONNECTION FOR COMBINED ROTATABLE AND OSCILLATABLE MINING TOOLS 4 SheesSheet 4 Filed June 29, 1951 J/fornqy Patented Nov. 17, 1953 POWER DRIVE CONNECTION FOR COM- BINED ROTATABLE AND OSCILLATABLE MINING TOOLS Robert A. McCallum, Clarendon Hills, 111., as-
signor to Goodman Manufacturing Company, Chicago, 111., a corporation of Illinois AppIication June 29, 1951, Serial No. 234,207
This invention relates to improvements in mining machines of the kind employing a powerrotated digging head with cutting bits mounted thereon, together with an out-of-balance weight rotatably mounted in said head to produce simultaneous rotation and vibratory movement of the head, whereby the digging action of the cutter bits is enhanced.
The invention consists more particularly in improvements in the type of mining machine broadly disclosed in the application of Charles E. Berry, Serial Number 142,489, filed February 4, 1950, and has for its principal object to provide improved supporting means and drive connections for the relatively rotatable digging head and vibrating weight.
A further object of the present invention is to provide improved power-drive connections whereby both the digging head and vibrating weight are rotated from a single drive motor.
A still further object of the invention is to provide improved drive gearing arrangements for producing certain predetermined cutting actions of the cutter bits, depending upon the relative speed and direction of rotation of the digging head and vibrating weight.
Further objects and advantages of the present invention will appear from time to time as the following description proceeds.
Figure 1 is a plan view of a mining machine including my improved form of vibratory digging mechanism;
Figure 2 is an enlarged detail view in side elevation of the vibratory digging mechanism shown in Figure 1;
Figure 3 is an enlarged detail section taken on line 33 of Figure 1;
Figure 4 is a detail side view of the digging head;
Figure 5 is a section taken on line 5-5 of Figure 3;
Figure 6 is a diagrammatic view showing the drive gearing for the digging head and off-center weight employed in the machine shown in Figures 1 to 5, wherein the digging head and weight are driven in opposite directions to each other;
Figure 7 is an enlarged fragmentary diagrammatic view illustrating the digging action or motion pattern of a cutter bit on the digging head which is driven by the gearing shown in the preceding figures;
Figure 8 is a diagrammatic view showing a modified form of drive gearing for the digg head and off-center weight, wherein the gear 2 ratio is changed so as to modify the motion pattern of the several digging bits;
Figure 9 is a diagrammatic view illustrating a modified digging action or motion pattern of the digging bits resulting from a change in gear ratio as shown in Figure 10;
Figure 10 is a diagrammatic View showing another modified gearing arrangement wherein the digging head and off-center weight are both driven in the same direction and at a different speed ratio;
Figure 11 is a diagrammatic view showing a modified digging action or motion pattern of the digging bits resulting from the gearing arrangement shown in Figure 10.
Referring now to details of the embodiments of my invention and, in particular, to details of construction of the digging head and power drive connections therefor which form the principal features of my present invention, I indicates a frusto-conical rotatable shell on which are mounted a plurality of bit supports 2, 2 adapted to receive bits or picks 2a in detachable engage- -ment therein projecting from the side walls of said shell. In the form shown herein, the bit supports 2 are arranged in a plurality of rows disposed in generally helical lines from the front to the rear ends of the shell, as shown in Figures 4 and 5. 3 is an off-center weight fixed as by keying on a front end section 4a of a drive shaft 4. The shell I is rotatably mounted on said shaft section la by a pair of antifriction ball bearings 5, 5 at the rear end of the shell and an antifriction roller bearing 6 at the front end of the shell.
The rear end of the shell is enclosed by a plate I detachably connected about its periphery to the rear end of the shell I and having the antifriction bearings 5, 5 supported in an inwardly extending recess Ia at the rear face of said plate. A centrally apertured retaining plate 8 is fixed to the plate l for holding antifriction members 5, 5 in recess 1a.
The drive shaft 4 comprises three integral sections, indicated at 4a, 4b and 4c. The rear section 40 constitutes the main bearing support for the shaft and is of substantially larger diameter than the other sections. The intermediate section db is disposed on the same axis as the inner section 40 and is somewhat smaller in diameter and of greater length than said inner section.
The front section 412, on which the off-center weight 3 is fixed and on which also the shell I is rotatably supported, as previously mentioned, is axially offset from the intermediate section 41) at a point immediately to the rear of the shell I.
The common longitudinal axis of the inner section 40 and the intermediate section 4b is indicated in Figure 3 by the line AC, while the length of the shaft of the inner section 40 is indicated at AB, and the length of the intermediate section is indicated at BC. The offset axis of the front section 411 is indicated in this figure at DE. In
the preferred arrangement shown, the axis DE of. w
the front or crank section 411 is substantially parallel to the main rotational axis AC. If desired, however, the axis DE, as extended rearwardly, might pass substantially through the point B at the juncture of sections 4c and 4bso that the angular deviation of axisDE with respect to the main axis AC might be represented; by the angle BBC.
The main axis AC, if extended; is arranged to pass substantially through the combined center.
of gravity of shell I and weight 3, for purposes to.be hereinafter more fully explained. My im.- proved digging mechanism, including a drivemotor. 9, is supported on a suitable platform I 9 which is bodily adjustable relative to a suitable mobile base ii for various digging movements, as will hereafter be more fully described. The dig-. ging mechanism and drive means therefor carried onframe it comprises the following:
The rear section 40 of main drive shaft 4 is journalled atits rear end in a self-aligning bearing unit l9 mounted in an annular ring Zfifixed.
in an upright support bracket 2! suitably fixed on the platform Hi. This self-aligning bearing unit permits limited orbital oscillatory movements of shaft 4 about the point substantially at A. A pair, ofretaining plates 22, 22 are fixed to opposite sidesof ring 2!] and extend inwardly to enclose the bearing unit l9.
A second upright suppor bracket 23 is suitably fixedvon the platform IE3 at a substantial distance from the first-named support bracket 2! for supporting the main shaft 4 at the point of juncture B between the rear section 40 and the intermediate section 42) of said main shaft. The
bracket 23fhas an, enlarged annular aperture 2 therethrough having two inwardly stepped shoulders 25 and 26 adjacent the rearof said aperture.
A metal, ring 2? has its periphery fitted in engagement with, the shoulder 25 while a second ring 28 is fitted in spaced relation near the front of the aperture 24-. A pair of discs 29 and 300i yieldable material such as rubber, herein of substantially the same internal and exterior diameter as the ring 2?, are secured as by bonding to the opposed inner faces of the rings 21 and 28; respectively. Theinner opposed faces of the two yieldable discs 29 and 30 are secured as by bonding to an outwardly extending plate 3! formed integral with a supporting ring 32. aligning bearing unit 33 is mounted in ring 32 which surrounds the frontend of the rear shaft section, of the main drive shaft 4. In the form shown, the ring 32 has a pair of retaining A selfplates 34, 34 fixed thereto and extending inwardthe rubber discs 23 and 30 are arranged to permit; limited radial shifting of supportingring 32 and.
bearing unit 33 withrespect to the supporting bracket 23 in response to rotary or orbital 0scillating movements of the shaft produced in response to vibratory action of the off-center weight 3, as will hereinafter be more fully described.
It willwbe observed that the oscillating movement. of the main shaft. 4 with respect to the bracket 23 centers about point A at the inner end of. the shaft 4, where the latter shaft is supported in the self-aligning bearing l 9 on the bracket 2|. Theshell l is driven. from motor 3 on platform l0- ata difierentspeed than the weight 3 and shaft 4 through separate power drive connections. In the form of drive gearing shown in Figures 1 to-3, thedrive connections for the shell l consist of .an internal gear 31 secured to the rear face of the retaining plate 8 and loosely meshed withexternal teeth 38 formed on the front endsof a hollow tubular shaft 33. The latter shaft surrounds the intermediate section 4b of vdrive.shaft.4,.in spaced relation thereto. The rear end. of the tubular shaft 39 has external teeth 49 loosely meshed with an internal gear 4| fixed as by bolts 52' to the hub of a spur gear;
The spur gear 44 is rotatably mounted on a hollow bearing 45 which surrounds the rear end of the maindrive shaft section 412 in spaced relation therefrom. The hollow bearing 45' is formed integrally with a supporting plate 46, the outer periphery of which is secured to. the front face of the supporting bracket 23 as by bolts 46a. The rearface of the supporting plate 46 also has an inwardly offset annular shoulder 4'." fitting within the aperture 25 in the supporting bracket.
23 to engage and hold in place ring 28 to which i one of the yieldable discs 30 is bonded.
The spur gear 44 is driventhrough a pinion 48' fixed on the front end of a shaft 49 which extends through and is journalled upon both the supporting bracket 23'and the supporting bracket 21 as by antifri'ction bearings 50 and Si. A spur gear 52is fixed on the rear end of the stub shaft land is engaged with the motor pinion 53 of motor 9'; The motor pinion 53'is also meshed with a gear 54Ionstub shaft 55 which is mounted coaxially with and connected for driving engagement with the rear end of the main shaft rear end'sectioncc of the main shaft 4; As seen in Figure 3, the stub shaft 55 has its rear end rotatably mounted in antifriction bearing unit 58 supported ina boss 51 fixed in a front face of a supporting plate 58for the frontend of'the' motor 9. The front end of the shaft 55is pro videdwith a plurality of spherical teeth 59 engaged with cooperating spherical teeth of anin ternal gear 60 which, in the form shown, is set in a recess portion 6i at the rear end of the shaft 4 and held therein as by studs BZpassing through flanges 33. The arrangement is such that the cooperating spherical gear teeth just mentioned" constitute a flexible coupling to provide a continuous drive connection between stub shaft 55 and the'main drive shaft 4 during all permissiblevibratoryor-oscillatory movements of the main shaft/ l while the machine is in operation.
The drive gearing above described-is such as to rotate the weight 3 in a direction opposite to that of the shell I with its cutter bits 2a. This gearingisshowndiagrammatically in Figure 6,
whereinthe gears are disposed-as seen from thefront of the machine-- Assuming that the motor pinion 53-rotates at .1150 R. P. M., the gears are arranged so as to drive the main shaft 4 and the weight 3 at'approximately 1950 R. P. M.,
and to drive the shell I in the opposite direotion at approximately- R. P. Me This affords -aspeed ratio of approximately 22 to 1, with weight 3 and shell I rotating in opposite directions.
A vibratory or oscillating movement of the shell I, weight 3 and the parts suspended for rotation therewith is set up by the rotation of the weight and shaft, as described. Any desired vibratory force may be obtained within permissible limits by selecting a suitable weight for the shell and its co-rotating parts, on the one hand, and a suitable weight for the off-center weight 3 and its co-rotating parts, on the other. When the parts are put into rotation, the shell will be caused to vibrate transversely or radially of the main axis AC of the drive shaft 4 approximately 23 times for each full rotation of said shell.
Considering now the path of movement produced at the point of each digging bit 2a on the shell I due to the combined rotation and vibratory movement of said shell, Figure 7 shows a motion pattern described by a single bit point in its plane of rotation as produced with a digging head driven by the gearing shown and described in connection with Figure 6.
As will be noted from the motion pattern of Figure 7, each bit point follows a generally circumferential path, but describes a series of successive loops 70 during each full rotation, which loops project outwardly or radially of the general axis of rotation of drive shaft 4. From the shape of these loops, it will be understood that each bit point makes about 23 successive relatively rapid outward picking movements toward the coal during each revolution of the shell. Moreover, the bit point momentarily reverses its forward movement just after it reaches each extreme limit of outward picking movement. This type of picking action is found to be especially effective in dislodging certain types of coal, as for instance friable coal, as it tends to dislodge such in larger lumps than is the case with other types of bit motions. It will be further understood that the motion pattern of the bit points shown in Figure 7 is that described withwhen the shell is in operation under varying digging loads against a coal face. In general, however, the several bits will constantly tend to approach the motion pattern shown as resistance of the coal decreases.
Another illustrative form of drive gearing is shown diagrammatically in Figure 8 which produces a motion pattern substantially as shown in Figure 9. In this form of gearing, the shell and weight are also rotated in opposite directions as before, but certain gears are of different sizes to produce a substantially lower ratio between the speeds of rotation of the weight and shell. Thus, in this modified form, pinion 48a is larger than the corresponding pinion 48 of Figure 6 and the gear 44a is smaller than the corresponding gear 44 of the latter figure. This change in gearing produces a ratio of substantially 8 to 1. The motion pattern of each cutter bit resulting from this reduced speed ratio is shown in Figure 9. As will be seen from this latter figure, the bit points now progress circumferentially about the general axis of main shaft 4 without any looped or retrograde movement. This type of bit action may be found to act more effectively in dislodging certain types of coal, such as socalled woody coals.
Figure 10 shows diagrammatically still another modified form of drive gearing for the vibratory assembly wherein both the weight 3 and the shell I are rotated in the same direction. In this form of gearing, the motor pinion 53 and the drive shafts 49 and 39 may be disposed in the same relationship to each other as before, but different sized gears are used on said shafts, in different meshed relationship. Thus, in Figure 10, the motor pinion I2 is meshed with a gear 13 which drives gear 54 on shaft 55 connected to the main drive shaft to drive the latter in a clockwise direction. The gear 13 also has gear 16 rotating therewith which is meshed with the gear 11. The latter gear rotates the tubular shaft 39 which drives the shell I in a clockwise direction, at a ratio of approximately 23 to 1. This results in the motion pattern for each bit point substantially as shown in Figure 11.
It will be observed from this motion pattern that each bit point follows a generally circumferential path including a series of successive loops H, but that said loops extend inwardly toward the approximate center of rotation of the shell instead of outwardly, as is the case with the looped pattern shown in Figure 7. This means that the bit acts with a picking action but remains in an outwardly projected shearing position relative to the coal fora longer period of time than is the case with the motion pattern shown in Figure '7. This modified motion pattern is particularly effective for certain types of coal which are more readily dislodged by a combined picking and shearing action.
The use and operation of my vibratory digging mechanism may now be described as follows:
The digging head mechanism mounted on platform l0 may be adjustably supported on any suitable base structure to position or move the digging head I into operative relation to the coal face, with the digging bits 2c in engagement with the coal. Many conventional base structures may be provided for this purpose. In the illustrative form of machine shown in Fi ure 1, the mobile base H is somewhat similar to that disclosed in the application of Charles E. Berry, Serial Number 142,489, hereinabove referred to, and includes a base frame 82 having a turntable 83 mounted thereon. The platform in carrying the vibratory assembly is mounted. for vertical pivoted movement relative to the: turntable by two upright hydraulic cylinders 84 disposed at widely spaced points near the front:
end of the turntable, to swing said platform about; trunnion supports 84a disposed toward the rearof said turntable. The base frame 82 may, as usual, be provided with a pair of endless tread supports 85 along opposite sides thereof, driven from motors 86, 86 on the rear end of the base frame. It will be understood, however, that the present invention is not limited to any specific form of supporting and adjusting means for moving or positioning the digging head with respect to the coal face, since such moving or posi tioning means may be varied widely in utilizing my improved form of vibratory digging head under different conditions of mining.
Accordingly, regardless of the form of means provided for positioning or moving the digging head into contact with the coal, the shell I with its digging head is moved by power into contact with the solid coal face so that the cutter bits 2a engage the coal and dislodge it in brokendown form for subsequent removal from the mine in any suitable manner.
While it is evident that the shell I may be 1' employedas adrilling or-boring to'olby feeding it forwardlyin thedirection" ,of'the-i general axis of rotation of the rotating parts, it: will be understood that the digging head operates most, effectively by swinging it in planeslaterally ortrans- "motor 9, brackets 2| and 23 and those portions of the drive gearing carried by said brackets provide a non-vibratorysupport for the vibratory assembly.
In practice, the shell and weight should be rotated at speeds in excess of the critical speed or natural period of vibration of the vibratory assembly because rotation at speeds below such natural period; of vibration causes most of the vibrations set up in the system to be transmitted to the supportingstructure. But, when the speed is increased above the natural period of vibration, the resulting vibrations are confined almost entirely to the vibratory assembly, and the effects of such vibrationsv on the platform It and base .I I are reduced to a minimum.
The arrangement, whereby the main drive shaft 4 constitutes the sole supporting means for both theweight 3 and the shell I, aids materially in utilizing'the vibrational effects on the vibratory assembly for dislodging the coal to the 'maximum, while reducing the effects of such vibrations "upon' the non-vibratory supporting mechanism to a minimum. As previously explained, the. main drive shaft 4 is rotatably supported so as to oscillate universally about the point A at'its extreme rear end. The amplitude of oscillation of this shaft, as well as the remainder of the vibratory assembly, is controlled by'the yielding discs 29 and 39, disposed at a substantial-distance forwardly of point A. The yielding discs 29 and Sll-constitute the only substantial supporting and dampening means for the entire vibrating assembly. The drive shaft 4 must therefore be of very substantial size and strength, as compared for instance with the tubular drive shaft 39 through which theshell l is .rotated, but which is flexibly connected to the shell so as to provide no transverse. support or dampening effect on the latter. The shell is rotatably mounted on the outer end section da of the main drive shaft 4 so as to-be entirely supported by the latter against endwise thrusts, transverse oscillations and transverse digging reactions of the vibratory assembly as the shell is in operative engagement with the coal.
Referring now in greater detail tothenovel arrangement wherein the general axis AC of the main drive shaft 4; when extended, passes substantially through the center of gravity of the shell I and the off-center weight 3 whilethe shell and weight'rotate' on the slightly offset longitudinal axis. DE, as previously described, the advantages 'of this arrangement may now be explained asfollows:
Assuming that themass of shell I isdistrib- .uted substantially uniformly about its own; axis of rotation DE, as will usually be the case, the
ever, is located at some point'on theopposite s de of the extended main axis AC so that said main axis and the centers of gravity of the shell and weight, respectively, are all in the same plane. The relative distance between the respective centers of gravity of the shell and weight from said extended'main axis will vary inversely with the total weights of the shell and weight, in accordance with a well-known law relating to relatively rotating bodies.
4 will tend to rotate in balanced relation about'the main axis AC when the parts are being rotated at normal-operating speeds, without any transverse load on the shell due to lateral contact with the coal face. Nevertheless-due to the axially offset mounting of the shell I in opposed relation to the center ofgravity of the off-center weight 3, the shell I will be simultaneously rotated and vibrated to produce a motion pattern for the digging bits such as illustrated in Figures 7, 9,,or 11, depending upon the speed ratio, and relative direction of movementof the shell and'weight. The eifects of such vibratory motion, however, will be almost entirely confined to the shell and weight, particularly when the parts are being rotated above the critical speed of the assembly, as previously described. When the digging head is moved laterally into digging engagement with the coal face, a resulting lateral thrust will tend to oscillate the drive shaft about point A at the extreme inner end of said shaft while any resulting deviation or oscillation effective on the shaft will be taken up by the yielding bearing support, including the rubber discs 29 and 30, which rotatably supports the drive shaft substantially at point B. As the digging head or shell works itself gradually into the coal face, the vibrating movements of the bits operating successively upon the 'coal face will dislodge the coal with a continuous combined picking and rotating movement, with the rubber discs 29 and 38 operating under shearing stresses, depending upon the amount of lateral pressure necessary for feeding the bits into the coal face.
' 1. In a digging machine, a frame, a main drive shaft rotatably supported on said frame for universal oscillatory movements relative to its normalaxis of rotation, said main shaft having, a portion at the oscillatory end thereof offset axially from the normallaxis ofsaid main shaft, .a hollow shell having peripheral digging. bits and rotatably mounted on saidaxially-offset portion of said main shaft, a weightfixed on said axially offset shaft portion, the center of gravity of said weight being axially offset from the main axis of said shaft a. direction opposite to, the offset portion of said shaft, and means for rotating said shell independently ofv said weight.
2. A machine in accordance with claim 1, wherein the normal axis of rotation of the main shaft is substantially in longitudinal alignment with the combined center of gravity of said shell and said weight.
3.,A machine in accordance with claim 1, wherein the means for rotating the shell includes a hollow drive shaft through which the main shaft extends, which hollow drive shaft has a universal-jointed connection with said shell in non-supporting relation thereto.
4. In a digging machine, a frame, a main drive shaft, means on said frame for driving one end of said shaft including a universal connection affording limited oscillation of the latter relative to its normal axis, bearing means intermediate the ends of said shaft affording limited yielding universal oscillation of said shaft, a hollow shell wholly supported in rotatable relation on the outer end of said shaft and having peripheral digging means thereon, an off-center weight fixed on the end of said shaft within said shell, and means on said frame for rotating said shell independently of said drive shaft including a hollow drive shaft through which said main drive shaft extends, said hollow shaft having a universaljointed drive connection with said shell in nonsupporting relation thereto.
5. A machine in accordance with claim 4, wherein the bearing means for the main shaft comprises an annular bearing member, an annular support on said frame surrounding said hearing member, and a disc of yieldable material in supporting relation between said bearing member and said annular support.
6. A machine in accordance with claim 5, wherein the disc is connected laterally between axially aligned portions of said bearing member and annular support, and is yieldable in shear in its own plane during oscillations of said main shaft.
7. In a digging machine, a frame, a main drive shaft, means on said frame for driving one end of said shaft including a universal connection affording limited oscillation of the latter about a fixed point coincident with its normal axis, bearing means intermediate the ends of said shaft affording limited yielding oscillation of said shaft universally about said fixed point, a hollow shell wholly supported in rotatable relation on the outer end of said shaft and having peripheral digging means thereon, an off-center weight fixed on the end of said shaft within said shell, and means on said frame for rotating said shell independently of said drive shaft, the bearing means for the main shaft including an annular bearing member, an annular support on said frame surrounding said bearing member, and a disc of yieldable material in supporting connection between said bearing member and said annular support and yieldable in shear during oscillations of said main shaft.
8. A machine in accordance with claim 7, wherein the bearing means intermediate the ends of the main shaft includes an antifriction bearing of the self-aligning type.
9. In a digging machine, a frame, a main drive shaft, means on said frame for driving one end of said shaft including a universal connection affording limited oscillation of the latter about a fixed point coincident with its normal axis, bearing means intermediate the ends of said shaft affording limited yielding oscillation of said shaft universally about said fixed point, a hollow shell wholly supported in rotatable relation on the outer end of said shaft and having peripheral digging means thereon, an off-center weight fixed on the end of said shaft within said shell, and means on said frame for rotating said shell independently of said drive shaft, the bearing means for the main shaft including an annular bearing member having a pair of opposed axiallyfacing cheeks, an annular bearing support on said frame surrounding said bearing member and having a pair of checks opposit the axially facing cheeks of said annular bearing member, and a pair of discs of yieldable material interposed between the two pairs of opposed cheeks and fixed thereto, so as to permit limited yielding of said bearing member both axially and transversely relative to said bearing support.
10. A machine in accordance with claim 4, wherein the means on said frame for rotating the shell also includes a gear rotatably supported on the bearing means and having the main shaft extending freely therethrough and connected through a universal joint with the rear end of the hollow drive shaft for the shell.
1. A machine in accordance with claim 10, wherein a drive motor is mounted on the frame and said drive motor is connected through independent gear trains for driving the inner end of the main drive shaft and the hollow shaft at different speeds.
12. A machine in accordance with claim 11, wherein the drive motor and intermediate drive gearing normally rotate the oscillatory assembly comprising the shell, the weight and their respective drive shafts, at a speed differing from the critical speed of said assembly.
ROBERT A. MCCALLUM.
References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 957,957 Hirst May 17, 1910 2,229,91 Baily Jan. 28, 1941 2,572,403 Stevenson Oct. 3, 1951 FOREIGN PATENTS Number Country Date 66,420 Norway July 5, 1943