US1643704A - A cobpoeatioh - Google Patents

Description

Sept. 7 1927' c, DAVIS POWER SHOVEL Fileksllu 12, 1926 5 Sheets-Sheet. 1

Five/250]" C/qarlesfl Davi y firm C. E. DAVIS POWER SHOVEL Filed Aug. 12, 1926 5 Sheets-Sheet 2 177091720? C/vc/rzesz 0 5 0 I 515% Huh,

C. E. DAVIS POWER SHOVEL Sept. 27.:

Filed Aug. 12, 1926 5 Sheets-Sheet 3 1,643,704 Sept. 27,1927. v CE DAVIS V 7 POWER SHOVEL Filed Aug. 12, 1926 s Sheets-Sheet 4 Patented Sept. 27, 1927.

UNITED STATES PATENT QFFICE.

CHARLES E. DAVIS, OF CHICAGO, ILLINOIS TO GOODMAN MANUFACTURING COMPANY, OF CHICAGO, ILLINOIS, A OGH-PORATION OF ILLINOIS.

POWER SHOVEL.

This invention relates particularly to power shovels for use in confined spaces such as in mines, although not limited to this use alone.

One of the objects of the invention relates to the provision of a power shovel which requires but comparatively little space for the horizontal operation of the scoop.

Other objects of the invention reside in the provision of a power shovel which is particularly adapted for use in confined spaces such as in mines with a view toward compactness, effective operation and proper control.

Referring to the drawings:

Figure 1 is a top plan view of a power shovel embodying one form of my invention with parts broken away and in section;

Figure 2 is a side elevation of the machine illustrated in Figure 1 with parts broken away and in section;

Figure 3 is a partial section on the line 3 of Figure 2;

Figure 4 is a partial section on the line 44. of Figure 1;

Figure 5 is a partial top plan view with parts removed broken away and in section;

Figure 6 is a top plan view with parts removed and in section;

Figure 7 is an enlarged partial section on the line 7-7 of Figure 1; and

Figure 8 is a partial section on the line H S of Figure 1.

Like numerals refer to like parts throughout the several figures.

In the drawings 1 designates a base frame which is carried on laterally spaced continuous tread devices 2 of usual construction which are adapted for the propulsion of the shovel.

The base frame 1 is provided with a cen trally disposed concentrically bored vertical hub 3 extending upwardly therefrom. A turntable or rotatable frame 4 is carried on the base frame and is journaled on said hub 3 for angular movement in a horizontal plane with respect to the base by means of a bored hub 5 formed integrally with the turn table and extending upwardly therefrom and journaled on the hub 3 of the base. See Figures 2 and 3.

Mounted for pivotal movement in a verw cal lane at the rear of the turntable as desigmttflrl at: 6, and extending; forwardip' Application filed August 12, 1926. Serial No. 128,731.

therefrom is an elevating frame '7 comprising' two vertically spaced horizontal portions secured together. The lower portion of the elevating frame 7 is provided with a concentrically bored hub 8 extending upwardly therefrom and surrounding the hub 5 of the turntable, the bore of the hub 8 being sufliciently large to permit pivotal movement of the elevating; frame.

A pair of crank arms 9 are disposed be tween the upper and lower portions of the elevating frame 7, and one of these crank arms is journaled on the hub 8 of the elevating frame while the other crank arm is journaled on the hub of the first mentioned crank arm. Thus are these crank arms 9 pivotally mounted coa Xially on the elevating frame on a vertical axis. V

The crank arms 9 are provided with gear scgmentportions 11 which mesh with re spective gears 12 secured on concentric shafts 13 disposed on a. vertical axis at the rear of the elevating}; frame 7 and journaled thereon. See Figures 1. 6 and 8. The shafts 13 extend above tle upper portion of the elevating frame, and secured on the upper ends of respective shafts 13 and facing each other are two bevel gears 14L. Secured on a horizontal transverse shaft 15 journaled on the elevating' frame 7 above the upper portion thereof is a third bevel gear 16 meshing with both of the bevel. gears 14. Thus is provided means for etlecting synchronous corresponding opposite angular movement of these crank arms.

A pair of links 17 is provided and each of these links is pivotally secured on vertical axes at respective ends thereof with the free end of respective crank arm 9, as designated at 18. and with a forwardly facing; scoop 19, as designated at 20. The links 17 are provided with arms 21 at the forward or scoop ends thereof. and these arms 21 extend transversely toward each other and have their free ends pivotally and slidably en- 'aged with each other midway between the links 17, as designated at 22.

As so carried the scoop 19 is vertically operable by operating the elevating frame 7 on its pivotal axis. Horizontal or radial moveineht the scoop is effected by operating rhe crank arms 9 angularly in oppesite rel ten bv ti" means above i. l. As an t...i*nt1 crank arms a i erated throughout a range from the positions thereof shown in Figure 1 to the positions shown in Figure 6. In this range of movement of the crank arms, the links 1'7 pivoting in an obvious manner carry the scoop l9 horizontally or radially and the arms 21 of the links 17, operating through the connection 22, serve to maintain the scoop in a Straight path of movement. The inner position of the scoop is shown in Figures 1 and 2 and in dotted lines in Figure 6 and the outer position thereof is shown in full lines in Figure 6.

The elevating frame 7 is operated on its pivotal axis 6 for vertically operating the scoop 19 and its carrying mechanisnrin the following manner. The turntable 4: is provided at its forward end with a rearwardly facing rack 24, curved on the aXis 6 of the elevating frame and extending upwardly from the turntable in substantially vertical disposition and between the links 17. See Figures 1, 2 and 5. Journaled on the upper portion of the elevating frame 17 immediately to the rear of the rack 1s a transverse shaft upon which is secured a gear 26 which meshes with the rack 21 for vertically operating the elevating frame with rotation of this shaft.

Power for operating the various mechanisms of the shovel is provided by an electric motor 27 mounted on the upper portion of the elevating frame 7 on the right hand side thereof. See Figures 1, 2, 3 and A transverse shaft 28 is journaled on the upper portion of the elevatingframe 7 adjacent the front end thereof, and mounted on this shaft is a manually controlled releasable frictional driving device 29 for driving the shaft. This driving device is operated from the motor 27 by a. gear train 30 driven by a gear 31 secured on the shaft of the motor. The shaft 28 is connected to drive the shaft 25 by means of a gear train 32, so that when the driving device 29 is engaged the gear 26 is rotated from the motor 27 to roll upwardly on the rack 24 and lift the elevating frame 7.

Thus is upward movement of the crank arms 9, linlrs 17, scoop 19 and the elevating frame 7 effected, and downward movement of the elevating frame 7 and the parts carried thereby is controlled as follows. Journaled on the upper portion of the elevating frame 7 and on the shaft 28 is a brake drum 3 1 provided with internal ratchet teeth 35. See Figures 1, 5 and 7. Pivotally mounted on a spider formation 36 of the driven member of the driving device 29, which is secured to the shaft 28, is a. plurality of pawls 37 which are yieldably urged into engagement with the ratchet teeth of the drum 3% by springs 88 whereby to form an automatic one-way driving connection between the shaft 28 and the brake drums 3 1. The outer surface of the brake drum 3: is a friction surface, and a friction brake band 39, adjustable by means of a usual adjustment device ll) and fixed against rotation by engagement in a slot in the elevating frame, as designated at ell in Figure 7, engages said outer surface of the brake drum 34- to form a friction brake therewith. The arrangement is such that the brake drum 34 is rotated with downward movement of the ele vating frame '7, and related parts, whereas the upward movement of the elevating frame and related parts is effected free of this brake by reason of the pawis 37 ratcheting over the ratchet teeth of the brake drum.

Another transverse shaft 43 is journaled on the upper portion of the elevating frame 7 rearwardly thereon, and. this shaft driven from the motor 27 by a gear train 4/1 driven by the motor gear 31. See Figures 1, 2 and 5. Mounted in this shaft 43 is a pair of manually controlled releasable frictional driving devices 45 of the planetary type. which are connected to drive another transverse shaft 46, journaled on the upper portion of the elevating frame 7 adjacent the sl'iaft 43, by means of respective of two gear trains @7, one of. which gear trains includes an additional idler gear 48 whereby the thalt el-G is driven in respective directions by the driving devices A gear train 49 has respertive gears thereof secured to the aforementioned shaft .15 and rotatably mounted on the shaft 456, and a manually c nitrrlled positive clutch member 50 is keyed on the shaft 46 for sliding n'iovement thereon to engage with and disengage from a corresponding formation. of the adjacent gear of the gear train 49 whereby to releasably drive the shaft 15 from the shaft ell When the clutch member 50 is engaged the thaft 15 may be rotated in either direc tion by manipulation of the driving devices 1-5 whereby to operate the scoop horizontally in respective directions in an obvious man,- ner.

A shaft 52 is journaled in the bore of the hub 53 of the base frame 1, the shaft being PlOVlflQCl with 7 an intermediate flange :52} which bears down ardly upon the upperend of the hub 25 to provide a downward thrust bearing for the shaft. See Figures 2 and The shaft 52 extends upwardly from the base frame 1 and through the axial openings of the turntable and crank arms 9 and a corres xuuling opening in the elevating frame. A jack element 54- is axially screwthreaded downwardly into an axial bore of the shaft 52 and is accordingly raised and lowered with rotation of the shaft 52, a transverse hole 55 being provided in the upper end of the jack element in which a rod may be inserted to prevent rotation of the jack element during rotation of the shaft to raise or lower the jack element. The jack element 5a is adapted for exerting lllll downward pressure from a roof or similar support for holding the shovel in place during operation thereof.

A downwardly facing bevel. gear is secured on the lower end of the shaft 52 be low the base frame 1, and secured on re spective of two coaxial transverse shafts 57 journaled on the base fame is a pair of bevel gears 58 which mesh with the gear 56 on opposite sides thereof for driving the shafts 57 in respective of opposite directions. See Figures 1, 2, 3 and 6. Chain and sprocket driving devices 59 serve to drive shafts 60 disposed coaxial with respective pairs of sprockets 61 of the continuous tread devices 2 from respective shafts 57 in respective opposite directions. Manually controlled positive clutch members 62 are keyed on the shafts 6") for sliding movement thereon adjacent respective sprockets 61 to engage with and disengage from respective of these sprockets for the selective driving of the continuous tread mechanisms 2. Thus by manipulation of the clutch members 62 the continuous tread devices 2 may be driven together in either direction to propel the shovel in a straight course. or driven in opposite directions for turning.

The opening in the upper portion of the elevating frame 7 through which the shaft 52 passes is relatively large and jourualed in this opening and. surrounding the shaft 52 is a large ring gear 63. See Figures 1, 2. 3 and 5. Keyed for sliding movement on the shaft 52 above the flange is a collar 64:, and a pair of alined studs are secured in diametrical relation on the collar and are slidably and pivotally engaged in respective of diametrically opposite apertures in a ring 66 surrounding the collar and within the ring gear 63. of alined studs 67 are secured in diametrical relation on the ring gear 63 and are slid ably and pivotally engaged in diametrically opposite apertures in the ring 66 disposed normal to the first mentioned apertures. Thus is the ring gear 63 rotatably fixed with the shaft 52 to permit vertical pivotal movement of the elevating frame 7 and with it the ring gear 63 on the axis 6 of the ele- *ating frame.

Journaled on the upper portion of the elevating frame 7 at the left'hand side thereof and extending forwardly and rearwardly is a shaft 68 and this shaft is driven from the shaft 43 by a pair of meshed bevel gears 69 secured on respective of these shafts. See Figures 1 and Mounted on the shaft 68 forwardly thereon is a pair of manually controlled releasable frictional driving devices 70 of the planetary type, which are connected to drive another shaft 71, journaled on the upper portion of the elevating frame 7 in parallelism with the A second pair shaft 68, by means of respective of two gear trains 72 one of which gear trains includes an additional idler gear 73 whereby the shaft 4.6 is driven in respective directions by the driving devices 70. A vertical shaft 74- is journaled on the upper portion of the elevating frame 7 adjacent the rear end of the shaft 71, and a pair of meshed bevel gears 7 5 secured to respective of the shafts 71 and 74 drives the shaft 74; from the shaft 71. A gear 76 secured on the shaft 74. meshes with the ring gear for driving thereon. A manually controlled releasable clutch device 77 is mount ed on the base frame 1 and is engageable with teeth of the bevel gear 56, as shown in Figures 1 and 2, for rotatably the shaft 52 and with it the ring gear 63 with the base frame 1 for angularly operating the turntable 4 on the base frame 1 by manipulation of the driving devices 70 in an obvious manner.

Another vertical shaft 79 is journaled on the upper portion of the elevating frame 7 between the shafts 46 and 74, and a worm {rear 66 is journaled on the shaft 79 and is engaged by worm 81 secured on the left hand end of the shaft 46 for driving the worm gear therefrom. See Figures l. 2 and A manually controlled positive clutch member 82 is keyed on the shaft 46 for sliding movement thereon to engage with and disengage from a corresponding formation of the worm gear whereby to releasably drive the shaft 7 9 from the shaft 46. A gear 83 is secured on the st aft 79 and meshes with the aforementioned gear 76 whereby to drive on the ring gear 63 through the worm 80 and worm 81. constituting reduction gearing, and the drivdevices 70.

The clutch 50 and the clutch 82 serve for alternately operating the crank arms 9 and driving on the ring gear 63. and it will be observed that a comparatively high speed drive is provided on the ring gear 63 through the driving devices 70 for angularly operating the turntable 4 on the base frame 1, and that an additional powerful reduction gear drive on the ring gear 63 is provided for effecting proper pressure on the jack element 54 and for driving the continuous tread mechanisms 2 for propelline the shovel.

When rotating the shaft 52 for raising or lowering; the jack element or for operating the continuous tread devices 2 the turntable is rotatably secured with the base frame 1 by means of a releasable locking device 84. of usual construction. See Figure 3.

The scoop 1.9 is provided with an ejector 85 operable longitudinally thereof for ejecting material from the scoop. This ejector is operated in the following manner. See

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Figures 1 and a. A pair of rack bars 86 are secured at their front ends to the ejector and extend rearwardly therefrom, and are slidably mounted in suitable bearings 87 carried with the scoop. Mounted on the rear of the scoop is a manually controlled reversible electric motor 88, and the racks are operated by reducing gear trains S9 driven by a gear secured on the shaftof this motor.

\Vhile I have shown herein and described one form of my invention, I do not wish to be limited. to the precise details of construction or arrangement of parts herein shown, and described, except as specifically limited in the appended claims.

I claim as my invention:

1. In a power shovel, the combination of a frame, a scoop, a pair of crank arms pivotally mounted on said frame, means for effecting angular movement of said crank arms in corresponding opposite relation, a pair of links each of which is pivotally secured with said scoop and with a respective crank arm, and means for maintaining a predetermined path of movement of said scoop.

2. In a power shovel, the combination of a frame, a. scoop, a pair of crank arms pivotally mounted on said frame for horizontal angular movement, means for effecting synchronous corresponding opposite angula movement of said crank arms, a pair of links each of which is pivotally secured at respective ends thereof with said scoop and with the free end of a respective crank arm on vertical axes, and mean operating between said links for maintaining a predetermined path of movement of said scoop.

8. In a power shovel, the combination of a frame, a scoop, a pair of coaxial crank arms mounted on said frame for pivotal movement on a vertical axis, means for effecting angular movement of said crank arms in corresponding opposite relation, a pair of links each of which is pivotally secured at respective ends thereof with said scoop and the free end of a respective crank arm on vertical axes, ant. arms on said links at the scoop ends thereof and. engaged for maintaining a predetermined path of movement of said scoop.

4. In a power shovel, the con'ibination of a frame, a scoop, a pair of era k arms pi votal y mounted on said frame, gear segments on said crank arms, a gear train operating between said segments for effecting angular movement of said crank arms in corresponding opposite relation, a pair of links each of which is pivotally secured at respective ends thereof with said scoop and with a respective crank arm, and. means for maintaining a predetermined path of moven'ient of said scoop.

5. In a power shovel,'ti;ic combination a? a:

resspoe frame, a scoop, a pair of coaxial crank arms mounted on said frame for pivotal movement on a vertical axis, gear segments on respective crank arms, a pair of coaxial gears meshing with respective gear segments, a pair of coaxial bevel gears facing each other and secured with respective of said first mentioned pair of coaxial. gears, a third bevel gear meshing with said pair of bevel gears for driving the same, a pair of links each of which is pivotally secured at respective ends thereof with said scoop and the free end of a respective crank arm, and arms on said links at the scoop ends thereof and engaged with each other for maintaining a straight path of movement of said scoop.

6. In a power shovel, the combination of a base frame, a turntable on said base frame mounted for angular movementin a hori- Zontal plane, an elevating frame pivotally mounted on said turntable for movement in a vertical plane, a scoop, and means carried by said elevating frame and carrying said scoop for horizontal movement including a pair of correspondingly oppositely operating crank arms pivotally mounted on said elevating frame for horizontal angular movement.

7. In a power shovel, the combination of a base frame, a turntable on said base frame mounted for angular movement in a horizontal plane, an elevating frame pivotally mounted on said turntable for movement in a vertical plane, a scoop, and means carried by said elevating frame and carrying said scoop for horizontal movement including a pair of coaxial correspondingly oppositely actuated crank arms pivotally mounted on said elevating frame in substantially coaxial relation with said turntable.

8. In a power shovel, the combination of a ase frame. a turntable on said base frame mounted for angular movement in a hori zontal plane, an elevating frame pivotally mounted on said turntable for movement in a vertical plane, scoop carrying means including a pair of correspondingly oppositely operating crank arms pivotally mounted on said elevating frame substantially on the axis of said turntable, a revoluble vertically disposed member carried independently of said elevating frame and extending through axial openings in said crank arms, a revoluble ring gear surrounding said revoluble member and carried by said elevating frame, and means for driving on said revoluble member from said gear ring adapted to permit pivotal movement of said elevating frame.

9. In a power shovel, the combination of a base frame, a turntable on said base frame mounted for angular movement in a horizontal. plane, an elevating frame pivotally mounted on aid turntable for nioverncnt in a vertical plane, scoop carrying means in eluding a pair of correspondingly oppositely operating crank arms pivotally mounted on said elevating frame substantially on the axis of said turntable, a revoluble vertically disposed shaft carried by said base frame and extending through axial openings in said turntable and crank arms and a corresponding opening through said elevating frame, a revoluble ring gear surrounding said shaft and carried by said elevating frame, and means for driving on said shaft from said ring gear and adapted to permit said pi movement of said elevating frame.

10. In a power shovel, the combination of ,a base frame, a turntable 011 said base frame mounted for angular movement in a horizontal plane, an elevating frame pivotally mounted on said turntable for movement in a vertical plane, scoop carrying means ineluding a pair of oppositely operating crank arms pivotally mounted on said elevating frame substantially on the axis of said turntable, and a vertical holding jack extending through axial o enings in said turntable and crank arms an a corresponding opening in said elevating frame.

11. In a power shovel, the combination of a base frame, a turntable on said base frame mounted for angular movement in a horizontal plane, an elevating frame pivotally mounted on said turntable for IllOVBIXlQIlt in a vertical plane, scoop carrying means including a pair of correspondingly oppositely operating crank arms pivotally mounted on said elevating frame substantially on the axis of said turntable, a revoluble vertically dis osed shaft carried with said base frame an extending upwardly through axial openings through said turntable and crank arms and a corresponding opening through said elevating frame, a revoluble ring gear surrounding said shaft and carried by said elevating frame, means for driving said shaft from said ring gear and adapted to permit said pivotal movement of said elevating frame, and a jack element axially screwthreaded downwardly on said shaft.

12. In a power shovel, the combination of a base frame, 1.)1'OIJt'llSlOI1 means on said base frame, a turntable on said base frame mounted for angular movement in a horizontal plane, an elevating frame mounted on said turntable for pivotal movement in a vertical plane with respect thereto, a revoluble member disposed coaxially with said turntable and carried independently of said elevating frame, means for driving said propulsion means from said revoluble member, and means for driving said revoluble mem ber from said elevating frame adapted to permit said pivotal movement of said elevating frame.

13. In a power shovel, the combination of a base frame, propulsion means carrying said base frame, a turntable on said base frame mounted for angular movement in a horizontal plane, an elevating frame mounted on said turi'itable for pivotal movement in a vertical plane with respect thereto, a rovoluble shaft disposed coaxially with said turntable and extending through openings in said base frame, said turntable and said elevating frame and carried on said base frame, means for driving said propulsion i'neans from said shaft, a revoluble ring gear surrounding said shaft and mounted on said elevating frame, and means for driving said shaft from said ring gear adapted to permit said pivotal n'lovement of said elevating frame.

fi l. In a power shovel, the combination of a base frame, a turntable on said base frame mounted for angular movement in a hori zontal plane, an elevating frame mounted on said turntable for pivotal movement in a vertical plane with respect thereto, a revoluble member disposed coaxially with said turntable and carried independently of said elevatii frame, a jack element axially screwthi aded on said revoluble member, and means for rotating said revoluble memher from said elevating frame adapted to permit said pivotal movement of said elevating frame 15. in a power shovel, the combination of a base frame, a turntable on said base frame mounted for angular movement in a horizontal plane, an elevating frame mounted on said turntable for pivotal movement in a vertical plane with respect thereto, a rev oluble shaft disposed eoaxiallv with said turntable and journaled on said base frame and extending upwardly through openings in said turntable and elevating frame, a jack element axially screwtl'ireaded downwardly on said shaft, a revoluble ring gear surrounding said shaft and mounted on said elevating frame, and means for driving said shaft from said ring gear adapted to permit said pivotal movement of said elevating frame.

16. In a power shovel, the combination of a base frame, propulsion means on said base frame, a turntable en said base frame mounted for angular movement in a horizontal plane. a power operated revolulol-e member disposed coaxially with said turntable, releasable means for driving said propulsion means from said revoluble member, and a jack element associated with said revoluble member for the raising and lowering of said jack element with rotation of said revoluble member.

l7. In a power shovel, the combination of a base frame, propulsion means on said base frame, a turntable on said base frame, mounted for angular movement in a" horizontal plane, a power operated revoluble iii:

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shaft carried with said base frame and disposed coaxially with said turntable and extending through an. axial opening therein, releasable means for driving said propulsion means from said shaft, and a jack element axially screwthreaded on said shaft.

18. In a. power shovel, the combination of a base frame, propulsion means on said base frame, a turntable on said base frame mounted for angular movement in a horizontal plane, an elevating frame pivotally mounted on said turntable for movement in a. vertical plane, a revoluble member disposed coaxially with said turntable and carried independently of said elevating frame, releasable means for driving said propulsion means from said revoluble member, a jack, element associated with said revoluble member for the raising and lowering of said jack element with rotation of said revoluble member, and means for driving said revoluble member from said elevating frame adapted to permit said pivotal movement of said elevating frame.

19. In a power shovel, the combination of a base, frame, propulsion means on said base frame, a turntable on said base frame mounted for angular movement in a horizontal plane, an elevating frame pivotally mounted on said turntable for movement in a vertical plane, a revoluble shaft disposed coaxially with said turntable and mounted on said base and extending upwardly therefrom through openings in said turntable and elevating frame, releasable means for driving said propulsion means from said shaft, a revoluble ring gear surrounding said shaft and mounted on said elevating frame, means for driving said shaft from said ring gear adapted to permit said pivotal movement of said elevating frame, and a jack element axially screwthreaded downwardly onsaid shaft.

20. Ina power shovel, the combination of a base frame a. turntable on said base frame mounted for angular movement in a horizontal plane, a revoluble member disposed coaXially with said turntable, releasable means for locking said revoluble member with said base frame, releasable means for locking said turntable with said base frame, means carried with said turntablefordriving on said revoluble member, and a jack element associated with said revoluble member for the raising and lowering of said jack with rotation of said revoluble member.

21. In a power shovel, the combination of a base frame. a turntable on said base frame mounted for angular movement in a horizontal plane, an elevating frame mounted on said turntable for pivotal movement in a vertical plane with respect thereto, a

revoluble shaft disposed coaxially with said turntable and carried by said base frame and extending upwardly through openings in said turntable and elevating frame, a revoluble ring gear surrounding said shaft and mounted on said elevating frame, means for driving said shaft from said ring gear adapted to permit said pivotal movement of said elevating frame, releasable means for locking said shaft and ring against rotation with respect to said base frame, means on said elevating frame including a gear mes-hing with said ring gear for driving on the ring gear, releasable means for locking said turntable against angular movement on said base, and a jack element axially screwthreaded downwardly on said shaft.

In a power shovel, the combination of a base frame, a turntable on said base frame mounted for angular movement in a horizontal plane, a revoluble member disposed coaxially with said. turntable, means for alternately locking said revoluble member andv said turntable with said base frame, manually controlled power operated means carried with said turntable for driving on said revoluble member, scoop carrying means carried with said turntable, a second manually controlled power operated means carried with said turntable, and means for alternately operating said scoop carrying means and driving on said revoluble member from said second power operated means including reduction gearing for driving, on said revoluble member.

23. In a power shovel, the combination of a base'frame, a turntable on said base frame mounted for angular movement in a hori zontal plane, a revoluble shaft disposed coaxially with said turntable and carried by said base frame, means for alternately locking said shaft and said turntable with said base frame, a pair of power operated oppositely acting manually controlled releasable frictional driving devices for driving, on said shaft in respective directions, scoop carry.- ing means carried with said turntable, a second pair of. power operated oppositely acting manually controlled releasable frictional. driving devices for driving in respective directions, a releasable positive clutch for operating said scoop carrying means from said second pair of driving devices, reduction gearing for driving on said shaft, and a second releasable positive clutch for driving said reduction gearing from said second pair of driving devices.

Signed at Chicago, in the county of Cook and State of Illinois, this 31st day. of July, A. D. 1926.

CHARLES E. DAVIS.

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