AU605790B2 - Power drive for working organ of industrial machine - Google Patents

Description

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1~ OflYBJIIKOBAHHM B COOTBETCTBI4HM C ALOrOBOPOM 0 rIATEHTHOfH KOorIEPAL11H4 (PCT) (51) MewKaIymapo~xan a J1CCIHtIIIKBW (11) Ho! Iep mew~yiiapogitofi ny6amnawu: WO 89/00259 H3o6peTeHjmA Al (43) Aa~a Ne~w~yiiHapflOH y6Ainnant: F16H 39/00,,47/02, 47/04, E02F 9/20 12 5[Haapl 1989 (12.01.89) (21) Homlep mew yiiapo9iuoif 3aABKII PCT/SU87/00080 (22) Ama r~tewgyiiapogioP, nogaqu: .1 wiqios 1987 (01.07,87) (71) 3a~lnwreah (6afi BcexyKcI3HHbJX 2ocyaapctne, Kpome US): MOCKOBOKHfI FOPHbf4 JHCTHTYT (SU/ SUI; MocKaa 117935, JIeHHHcKui rip,, 6 (SU) [MOSKOVSKY GORNY INSTITUT, Moscow (72) HW-o6peraTenw, ii H3o6peTaTejju/3aaniffeJm~ (MOlzbx rvI Lus): flo.1qP- H14 POWaH I0pbeBHwI [SU/SU]; MOCicBa 119121, yji, CmoJneHcKaSI, 7, K8a, 82 (SU) [PODERNI, Rom~an Jurievich, Moscow MYXAMEJaOB MapaT XaHabhiseaBt [SU/SU]; MocKa 1 13105, BapwaBc~oe Luocce, 2, KB, 334 (SU) [MUKHAMEDOV, Marat Khanafievich, Moscow XPOMOI4 Mitxai PyBHMOBH' [SU/SU]; MOCKa 117418, yn., UyplOnbl, a. 11, KUprI. 3, KB, 207 (SU) [KHROMOI, Mikhail Ruvimovich, Moscow CAHJZAJIOB Bna~akimip 00zQop0B14% [SU/SU]; PeYTOB 143952, MOClcoBcxasi o6ii., Banau1HHiHCKlHf paffoH, Y ".OMycomojlbcKaql, 3, KB. 72 (SU) [SANDALOV ladimir Fedorovich, Reutov (SU)I. CKYPbIJIHH f:opHc I4BaHOBWI [SU/SU]; MocKBa 121359, yir. Mapmua TtimoLmeHKO, gt. 26, KB, 32 (SU) [SKURYDlN, Boris Ivanovich, Moscow IIlAMvIIIAaIHHOB Pawmn Axm~e-roaiq [SU/SU]; MOCKBa 115407, yn. 3a- TOHHag, g. 7, Kopn. 1, KB3. 96 (SU) [SHAMSHADI- NOV, Rashid Akhmetovich, Moscow H03E- HAC I0piti reniteBMi [SU/SU]; Mocicaa 107258, 6yfibaap PoKocconcKoro,g, 36, KOpMi 1, KB3. 145 (SU [IOZENAS, Jury Gelievich, Moscow (74) Areirr: TOPrOBO-flPOMbIIIJIEHHAA flAJIATA CCCP; MOCKBa 103735, yji, Kyfl6biumeBa, g. 5/2 (SU) [THE USSR CHAMBER OF COMMERCE AND INDUSTRY, Moscow (81) YKa3ainmie rocygaapCTBa: AT, AU, DE, Fl, HU, IT, JP, SE, US Onty6RJunBaiia C omltemowi o ,si eoxIy-apo3Ho~v noucxe (54) Title:POWER DRIVE FOR WORKING ORGAN OF INDUSTRIAL MACHINE (54) Haimne II306pe~zemixa CHJIOBOII HP1HBO PAIOtIEI'o OPPAHA riPOMbIIIIJE-!HOII MAIIH4HbI (57) Abstract MA 8 A power drive for the working AUSTRALIA1 organ of afl industrial machine is mounted on its support frame and AN9 com~p rises a multi-element planetary DiPATENTOF mechanism (24) and a driving motor F The input shaft (26) of the mel chanlsm (24) Is connected to the shaft 26 (27) of the driving motor and the output shaft Is kinematically connec ted to the working organ of the ma' J chine. The power drive (22) is provi- L70 j ded with a m~eans for protection 2 against static and dynamic overload- '4 46 I ing, wl-ic consists of a volume hy.

dromachine (40) mounted, together 6 with Its high-pressure line (42) and -62 low-pressure line on the support 76J7 7962 7 ianie or the Industrial machine, 7J /76 The shalt, (44) of the volume hydromachine (40) is connected, through a27 W transmisi~n, to an elenient (29) or 67 the planetatry mechanism (24) accept- 11 f F- 7 Ui frig Its reactive torque, 6 6 (l7 9

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Thi's document contains the 07 amendments made", tinder Section 49 and is correct for Printing GRIFFITH HASSEL FRAZER G.P.O. BOX 4164 SYDNEY, AUSTRALIA I

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CF p ecnyAnlta CG iQro CNM KaMapylt DIE tkagqitllag Po~lyd~DUCa re0Ifilf Fl tbmins~ tpa~tum radooz Be~ltopli-aiflis IDe~irpiig Illarn Wolft Iag Thollakoyp Manarcica NML Mainit N1R cipti-awIift NO fto-nwrmR SD cyauif SE [Uaguli SN clltan 'r Tioro US COmiltifth RfltLt Astaosixit POWER DRIVE OF THE WORKING ELMIENT OF AN INDUSTRIAL

MACHINE

Technical Field The present invention relates generally to industrial mechanical engineering and more specifically to power drives of the working elements of industrial machines.

The present invention can find most utility when applied to mining, materials handling and earth-moving machinery, as well as in rolling-mill and preswor:.ing equipment.

Prior Art One of the most critical problems encountered in exploitation of an industrial machine resides in how to provide reliable operation arid long service life of the drive of its working element, which is subjected to heavy static and dynamic overloads both under routine operating conditions and especially during 'the starting-up procedure that involves overcoming ok the forces oif inertia of the drive flywheel mass at rest, as well as during shut-down of the drive due to a sudden surpassing of the counteracting forces over the drive motive power.

The drive of an indust,'ial machine establishes a closed resonant circuit with the working element of the machine during its operation, wherein fatigue failure of the drive components is liable to resLlt from the onset of resonance condition, and said comp,inents are liable to loose strength upon sudden surpassing of the counteracting forces over the drive motive power.

In the case of an industrial machine Whose working element is actuated by a nlmber of drives, there occurs as a, rule, the state of static indeterarinacy of the load in each of the drive transmission mechanisms, resulting in additional static and dynamic loads on their components.

Attempts made to hsolve that problem resulted in the provision of a power drive of the working element of an 2 industrial machine, incorporating a means for preventing the drive from static and dynamic overloads and finding extensive application up till now.

The power drive of a working element, the bucket wheel of an industrial machine, that is, a bucket wheel excavator, as described in DE, A, No. 1112465 is composed of an electric motor and a triple-link planetary mechanism.

Tht latter comprises a first link, a sun gear connected to the electric motor shaft, a second link, i.e., an internal gear connected to the working element of the machine, namely, with the excavator bucket wheel, and a third link, a planet carrier which is connected,via a kinematic chain, to the load-bearing structure of the bucket wheel beam adapted to take up the drive reactive torque.

The internal gear is positioned concentrically with the sun gear and is in mesh with the planet pinions, which in turn are in mesh with the sun gear. The planet pinions are secured on the carrier through their shafts.

Kinematic association of the planet carrier with the boom load-carrying structure, is established by a hollow shaft connected via one of its ends to the planet carrier and by its other end, to one end of an arm whose other end is connected to springs held to the load-carrying structure of the bucket wheel excavator boom.

The aforementioned springs serve as a means to safeguard the excavator against dynamic overloads in the heretofore-known construction of the power drive.

During the starting-up procedure the inertia forces of the drive flywheel mass at rest which act within the entire period of the electric motor acceleration till it gains the rated speed, are taken up by the gear pairs of the planetary mechanism, the hollow shaft, the arm and the springs, which as a rule results in loss of strength by the drive components.

-3- With the bucket wheel excavator operating under rated conditions its drive and bucket wheel establish a resonant circuit, wherein the onset of mechanical resonance is ruled out at only one of the drive natural frequencies accounted for by the linear hardness of the springs, whereas resonance conditions are liable to occur on some other drive natural frequencies, resulting in fatigue failure of the drive components and in that of the components of the bucket wheel and the bucket wheel excavator load-carrying structure.

A sudden surpassing of the forces counteracting the crowding force of the excavator over the drive mutive power, which may be due to an abrupt increase in the hardness of the material being excavated, the components of the bucket wheel, drive, etc., loose their strength due to rest-icted compliance of the springs.

The known drive of the bucket wheel of a bucket-wheel excavator under discussion fails to provide its reliable prevention against static and dynamic overloads, especially during the starting-up procedure and in cases where the drive motive power is surpassed by the crowding counteracting forces.

Attempts at the provision of a power drive of the working element of an industrial machine featuring a more reliable means for its prevention against static and dynamic overloads, especially in cases where the drive motive forces are exceeded by the forces counteracting the crowding force have resulted in the development of another power drive of the working element, a bucket chain, of an industrial machine, a chain bucket excavator as described in a book "Iulti-bucket excavating machines" by N.G. Dombrovsky, 1972 Miashinostroenie Publishers, Mvoscow, pp. 153-154 (in Russian).

I

i i i ii: -4 The known power drive of the bucket chain of a bucketchain excavator is built up of an electric motor and a triple-link planetary mechanism. The latter incorporates a first link, a sun gear mechanically associated with the electric motor shaft, a second link, a planet carrier which is connected, via a hollow shaft, to the working element, viz., the driving sprockets of the bucket chain, and a third link, an internal gear connected, through a mechanical transmission, to the load-carrying structure of the bucket-chain excavator adapted to take up the drive reactive torque.

The internal gear is set concentrically with the sun gear and is in mesh with planet pinions, which in turn are in mesh with the sun gear and are secured through their shafts on the planet carrier.

Mechanical association of the internal gear with the load-carrying structure of the bucket-chain excavator is established by rollers adapted to interact with the outside surface of the internal gear rim, the shafts of said rollers being held to the frame that encompasses the internal gear rim and is articulated to the springs secured on the load-carrying structure of the bucket-chain excavator.

In the heretofore-known construction of a power drive a means for preventing the bucket-chain excavator against static and dynamic overloads is a frame-mounted normally engaged brake whose shoes are adapted to interact with the outside surface of the internal gear rim, and springs.

Whenever the motive forces of the bucket chain drive are suddenly surpassed by the forces resisting the excavator crowding force, the frame is turned, within a preset rate of the springs, at the end of which the rim of the internal gear is released, thus interrupting the mechanical linkage of the bucket chain with the electric motor, resulting in free damped vibrations with a large 5 initial amplitude arising in the drive and in the loadcarrying structure of the bucket-chain excavator. This causes failure of the bucket chain links, the drive components and the load-carrying structure of the bucket-chain excavator.

The forces of inertia of the drive flywheel mass at rest that act within the entire period of the electric motor acceleration up to its rated rotational speed during the drive starting-up procedure are taken up by the pairs of gears in mesh of the planetary mechanism, the hollow shaft, the frame, and the springs. This as a rule results in loss of strength by the drive components.

With the bucket-chain excavator operating under rated S' conditions its 4rive and bucket chain establish a reso- 15 nant circuit, wherein the onset of mechanical resonance is ruled out at only one of the drive natural frequencies accounted for by the linear hardness of the springs, whereas resonance conditions are likely to occur on some other drive natural frequencies, resulting in fatigue failure of the drive components and in that the components of the bucket chain and of the bucket-chain excavator load-carrying components.

The known drive of the bucket chain of a bucket-chain excavator under discussion fails to provide its reliable prevention against static and dynamic overloads, especially during the starting-up procedure and cases where the drive motive power is surpassed by the forces resisting the crowding forces. Moreover, the drive in question features a relatively sophisticated construction of the braking device of the planetary mechanism ring,gear rim.

6 Summary of the Invention Accordingly, the present invention provides a power drive of the working element of an industrial machine, situated on its load-carrying structure, incorporating a multiple-link planetary mechanism having a gearing arrangement adapted to take up the reactive torque developed by the planetary mechanism, the input shaft of the mechanism being connected to the shaft of an actuating motor, the power drive having an output shaft operatively associated with the working element of the machine, and a means for protecting the power drive against static and dynamic overloads, characterized in that the means for protecting the power drive against static and dynamic overloads is in effect a hydrostatic machine held to the load-carrying 15 structure of the industrial machine and having a Shigh-pressure line and a low-pressure line the high-pressure line and the low-pressure line formi.g part of a hydraulic S. circuit, a shaft of the hydrostatic machine being connected, oo through a mechanical transmission, to the gearing arrangement of the planetary mechanism that is adapted to take up the torque developed by the mechanism.

An advantage of a preferred embodiment cl the present invention is that it may provide a power drive of the working element of an industrial machine, wherein constructional modifications of a means for prevention of the drive from static and dynamic overloads and of the mechanical linkage of the drive to the planetary mechanism link adapted to take up the drive reactive torque and to the industrial machine load-carrying structure, would be 30 instrumental in limiting the amount of powier load on the working element and in ruling out any resonance conditions at practically all natural frequencies of the drive.

81774S/SLT 1, The power drive of the working element of an industrial machine according to an embodiment of the present invention ensures constant mechanical association between the link of the drive planetary mechanism that takes up its torque, and the load-carrying structure of the industrial machine during the drive starting-iup procedure, under its rated operating conditions and in the case where the drive motive power is exceeded suddenly by the forces resisting the working element of the machine. The aformentioned constant

S

*C

o0 1774S/SLT -7stant mechanical association under the abovesaid operating conditions3 of the industrial machine is attained by virtue of a power liquid contained under a pressure in the hydrostatic mnachin~e which serves as an elastically damping element.

It is expedient that the high-pressure line of the hydrestatic machine be connected to a hydraulic accumulator through a throttle check valve, and to the low-pressure line through a hydraulic directional control valve and a controlled throttle valve, both being arranged in series as along the flow of the power liquid.

Such a construction arrangement of the drive of the working, element of an industrial machine makes it poosible to convert the load torque applied to one of the links of the planetary mechanism into the torsional vibrations of the hydrostatic machine shaft and to preclude development of resonance conditions at the drive natural frequencies due to circulation of the power liquid under pressure along a hydraulic circuit established by the working chambers of the hydrostatic machine, the high-pressure line, the throttle check valve and the hydraulic accurialat,or, -thus rulling out any fatigue failure of the drive comnpone,,ts.

Upon bringing the drive into action -the forces of inertia of its flywheel mass at rest are taken. up by the power liquid that circuiltes under pressure along a hydraulic circuit constituted by the high-pressure line, the hydraulic directional control valve, -the controlled throttle valve and the low-pressure line, which enoures against failure of the drive components.

It is recommended that used as a hydrostatic machine be the one provided with a mechanism for control of the volume of the hydrostatic machine working chambers, said mechanism being made as a hydraulic cylinder held in place within the housing of the hydrostatic machine, the rodend chamber of said, hydraulic cylinder being hydraulical.

ly connected, through a safety valve, to the high-pressure line of' the hydrostatic machine and through the throttle check valve, to the low-pressure line, while the head-end chamber of' the hydraulic cylinder is reasonable to be provided with a spring whose one end is connected to the h~ydraulic cylinder barrel, and its other end is connected to kj the piston, which heea-end chamber is expedient to be hy- I draulically connected to the drainback.

Such a construction arrangement of the drive restricts the amount of power load on the working element of an industrial Machine in the case where the drive motive power is suddenly exceeded by the forces resisting the working element of' the industrial machine, by reducing the volume of' the working chamibers of' the hydrostatic machine accompanied by circulation of the power liquid under pressure along a hydraulic circuit established by the working chnfmbera of' the hycroota%1ic machine, the high-pressure line! the safety valve, the throttle chock Valve, and the lowpreoouve line of' the 4ydroetatic m'ahine, which rules out any failure of the drive components and the load-carrying structure of' the Industrial mnachine.

It lt desirable that the power drive be provided, with at least one more mltiplo-lin'k planetary iaechanism whose Input shaft In connected. to -the shaft of a second actuating motor, while its output is operatively associated with the working element of the idustrial machine, nnd the link of the Oecond planetar~y uisohnim that takes up Its reactive torque is conxieotecl, through a mechanical transmisilon, to the shaflt of a second hydrostatic machine which is held to tho load-caryng OttetuM' of' the Industrial Inacine, said second hydrostatic rnaohIv.s comprising a high-pressure line hydzraullcally connected to the nimilar line of tho tirst hydr'ostatic machine, a low-prossure line hydzaulioally connected to the similar line of the first hydrostatic machine, and, a mechanism for coht- Nook 9 -9rol of the volume of the working chambers of said second hydrostatic machine, said mechanism being made as a hydraulic cylinder fixed in position inside the housing of said machine, the head-end chamber of said hydraulic cylnder being provided with a spring whose one end is connected to the hydraulic cylinder barrel, and its other end is connected tohe piston, which head-end chamber is hydraulically communicated with the drainback, while the rod-end chamber of said hydraulic cylinder is hydraulically connected to the rod-end chamber of the hydraulic cylinder of the mechanism for control of the volume of the working chambers of the first hydrostatic machine.

Such a construction arrangement provides for reasonable positioning of the drive of the working element on the load-carrying structure of the machine, while the hydraulic communication between the similar lines of the hydrostatic machines rules out static indeterminacy of the load on each of the drive planetary mechanisms, thus adding to the durability of the drive components and Of the load-carrying structure of the industrial machine.

When making use of an industrial machine, wherein provision is made for a feed traverse mechanism of the working element and for a working element rotation power drive made in accordance with the invention, it is recommended that the feed traverse mechanism of the working element be made as at least one hydraulic power cylinder operatively associated with the working element and fastened on the load-carrying structure of the industrial machine, one of the chambers of said hydraulic power cylinder being hydraulically communicated with the highpressure line of one of the hydrostatic machines, and the other chamber is hydraulically connected to the rod-end chamber of the hydraulic cylinder of the mechanism for control of the volume of the working chambers of the same hydrostatic machine.

10 Such a hydraulic communication established between the hydraulic. cylinder chambers arid the pressure lines of the hydrostatic machine affords protection of the working element feed traverse mechanism against static and dynaoverloads during its otarting-up procedure and at its shut-down occurrinig when the drive motive power is suddenly excceeded by the forces counteracting the rotary motion of the working element, which reduces fluctuation and limits the maximum value of the power liquid pressure effective ,In the hydraulic Qylinder.

8 umma ry of the Drawings Other objects and advantageous features of the inventio wil bcoe mre pprent from a c ons ration of the following specific einbodimato thereof with referexice to the accompanying drawingswhereln:, FXGQ. 1 is a ,,neial ochematic view of a bucket wheel excavator for excavatine, and transpoiting th exaaed, mock to the place of Ito loading, incorpor'ating a power drive for rota~tion of tho bucket wheel made accordling -to invention, and a reversible power drive of the exccavator ouperotruoturet Rccordine. to the invention; 1FXG- 2 Is a scalod-up secti~onal viewi takon, rUona thie line XX-2E in PIG.. 1, as z'evolved t ero O unterclockwioe for clarity; FIG. 3 in a scalod-up oectionol vio, iikori al~np, the line 1tX-XX In PIG. li; 1VXG- 4 Is a soaled-up view faoirid the aZrrow A in PIG. 1, with 'the supocvstrioture o± the bucoket wheel excavator out of poeiIton; JPIG. 5 ±ti a view of' a mochanical a~nd hydz'aulic j,cuit diagramn of the power dz'ivo for rotatij Q W cavator bucket wheelt aordtia~t to W4 1tunionli 1110 is a view of a 4~ia hyd*Zattlla aircuit diagram, of the povwez, drj ,mchnir of the buokot wh,961 exaaVo 11 FIG. 7 is a general schematic view of an opencast drillrig for drilling vertical and inclined holes, provided with the power drive of a drill rod string, according to the invention; PIG. 8 is a view facing the arrow B in FIG. 7 (the right-hand half of the drill tower being omitted); FIG. 9 is a view of a mechanical and hydraulic circuit diagram of a power drive of the drill rod string of an opencast drillrig, according to the invention; and FIG. 10 is a scaled-up view of a section taken along the line X-X in FIG. 8.

Preferred Embodiments of the Invention The multibucket wheel excavator designed for, e.g., coal winning comprises a bucket wheel 1 (FIG. 1) provided with buckets 2 secured on a wheel plate 3 (FIG. 2) rigidly linked to a hollow shaft 4 which rests on supports of a boom 6 (FIG. 1) of the wheel 1, a receiving conveyor 7 mounted on the boom 6, a cantilever 8 with a discharge conveyer 9, said cantilever being articulately connected to a front leg 10, and a crawler mechanism 11. One of the ends of the boom 6 is articulated to the top portion of the front leg 10, while its other end is articulated to a piston rod 12 of a hydraulic cylinder 13, which is in turn articulately associated with the bottom portion of the front leg The boom 6, the cantilever 8, the front leg 10 and a counterbalance weight 14 which is rigidly linked to the front leg 10, establish a superstructure 15 (FIG. 1) which is in fact the load-carrying structure of the bucket wheel excavator, which superstructure is mounted on a frame 16 of the crawler mechanism 11 with a possibility of swinging .in a horizontal plane. Swinging of the superstructure 15 with respect to the frame 16 is carried out by means of roller.s 17 (FIG. 3) interacting with guideways 18 and 19 which are secured respectively on the suamendments made under uu Section 49 and is correct for printing 12 perstructure 15 and on the tooth rim of a gear 20 of a power drive 21 (PIG. 4) for swinging the superstructure (FIG. 1).

A bucket wheel power drive 22 is composed of an electric motor 23 secured to the boom 6 and a triple-link planetary mechanism 24, which comprises a first link, i.e., a sun gear 25 held to an input shaft 26 operatively associated with a shaft 27 of the electric motor 23, a second link, a planet carrier 28 connected, through the hollow output shaft 4, to the wheel plate 3 of the bucket wheel 1, a third link, an internal gear 29 having internal and external toothings and arranged concentrically with the sun gear 25 so as to mesh, through its internal toothing, with planet pinions 30 which in turn are in mesh with the sun gear 25. The planet pinions are held with their shafts to the planet carrier 28. The shaft 26 is accommodated in the hollow shaft 4. The sun gear 25, the planet carrier 28, the planet pinions and the internal gear 29 are accommodated in a housing 32 rotatably mounted in supports 33 and in bearings 34 which are fixed on the boom 6. The internal gear 29 is rigidly coupled with the housing 32.

The kinematic association between the shaft 26 and the shaft 27 is established by a bevel gear 35 set on the shaft 26 and meshed with a bevel pinion 36 set on a shaft 37 which is connected, through a coupling 38, to the electric motor shaft 27. The pair composed of the bevel gear and the bevel pinion 36 is accommodated in a housing 39 held to the boom 6 (fIG. 1).

The power drive 22 is provided with a means for its protection against static and dynamic overloads made as a hydrostatic machine 40 having a mechanism 41 (FIG. adapted to control the volume of the working chambers (omitted in the Drawing) of said hydrostatic machine, a high-pressure line 42 and a low-pressure line 43. A shaft 1 4 13- 44 (FIG. 2) of the hydrostatic machine 40 is connected, through a mechanical transmission, to the third link of the planetary mechanism 24. The mechanical tranemission is made as a pinion 45 and the internal gear 29 of the planetary mechanism 24. The pinion 45 is held to the shaft 44 of the hydrostatic machine 40 and is in mesh with the external toothing of the internal gear 29. The pinion is accommodated in a housing 46 which is secured on the boom 6, and is mounted on a support 47. The hydrostatic machine 40 is fixed on the housing 46. The high-pressure line 42' of the hydrostatic machine 40 communicates, through a throttle check valve 48, with a hydraulic accumalator 49 and via a two-position hydraulic directional control valve 50 and a controlled throttle valve 51, both being arranged in series as along the flow of the power liquid, with the low-pressure line 43. The throttle check valve 48 comprises a throttle valve 52 and a check valve 53 arranged in parallel. The hydraulic directional control valve has a spring 54 and a hydraulic pilot spool 55 conuunicating ith the high-pressure line 42 through a hydraulic line 56. The controlled throttle valve 51 has a piston 57 with a variable-section rod 58, an inlet collector 59 communicating, through a hydraulic line 60, with the hydraulio directional control valve 50, an outlet collector 61 hydraulically connected with the low-pressure line 43, an annular throttle orifice 62 communicating with the inlet P collector 59 and with the outlet collector 61, a control chamber 63 subdivided by the piston 57 into oubchambers 64 and 65. The stbchamber 64 is situated ot the end of the piston rod 58 and is hydraulically coraiected, through a check valve 66, to the line 43, and through a controlled throttle valve 67, to a drainback 68. The subchamber is located at the end of the piston 57 and is hydraulically connected, through a pressure reducing valve 69, to the inlet collector 59 of tlhe controlled throttle valve 51, and through a throttle vali;e 70, to the drainback 68.

14 The end face of the piston rod 58 of the controlled throttle valve 51 rests upon a spring 71 located in a chamber 72 which is hydraulically connected to the drainback 68. The mechanism 41 for control over the volume of the working chambers of the hydrostatic machine 40 is made as a hydraUlic cylinder 73 secured in position within the housing of the hydrostatic machine 40. The hydraulic cylinder 73 has a rod 74 and a piston 75 which subdivides the interior space of the cylinder 73 into chambers 76 and 77. The chamber 76 is located at the end of the rod 74 and is hydraulically communicated with the line 42 via a safety valve 78, and with the line 43 through a throttle check valve 79. The chamber 77 is located at the end of the piston 75 and is provided with a spring 80 whose one end is connected to the barrel of the hydraulic cylinder 73, while its other end is connected to the piston 75. Ihe chamber 77 is hydraulically communicated with the drainback 68.

The throttle check valve 79 incorporates parallel arrarged a throttle valve 81 and a check valve 82. The outlet collector 61 of the controlled throttle valve 51 is connected to a means (device) 83 to compensate for leaks of the power liquid, hereinafter referred to as the power liquid leakage refiller, which is hydraulically communicated with the drainback 68. The hydraulic accumulator 49 comprises an elastic diaphragm 84 which subdivides the interior space of the hydraulic accumulator 49 into two chambers 85 and 86 isolated from each other. The chamber 85 is hydraulically communicated, through the throttle check valve 48, with the high-pressure line 42. The chamber 86 is gasfilled.

The power drive 22 for rotation of the excavator bucket wheel operates as follows.

Prior to starting the drive 22 (FIG. 5) the piston with the rod 74 of the mechanism 41 for control over the volume of the working chambers of the hydrostatic machine hi-_ assumes its leftmost position tinder the tension of the spring 80, which positi~on correspondz to t1,he maximum volume of the working chambers of the hydrostatic machine the hydraulic directional control -valve 50 actuated by the tension of the spring 54, establishes hydraulic communication between the line 42 and the inlet collector 59 of the controlled throttle valve 51, as well as the pressure, reducing valve 69; the piston 57 with the rod 58 of the controlled throttle valve 51 is in Its rightmost position being held therein by virtue of the force developed by the spring 71, which corresponds to the maximum throttling area of the annular throttle orifice 62.

Upon putting the drive 22 in operation the power liquid leakage refiller 83 feeds the power liquid from -the drainback 68 to the outlet collector 61 of the controlled throttle valve 51, to the hydraulic line 43, to the chamber 64 of the controlled throttle valve 51 through tho check valve 66, and to the chamber 76 of the hydraulic cylinder 73 th.ough the throttle check Valve 79. Once -the electric motor 23 has been switched on, the latter imparts rotation to the shaft 44 of the hydrostatic machine 40 through the shaft 27, the coupling 38, the shaft 37, the bevel pinion 36, the bevel gear 35, the shaft 26, the earn gear the planet piniono 30, the internal gear 29 and the pinion 45. As a result, the power liquid is fed from the working chambers (omitted in the Drawing) of the hydrostatic machine 410 along the line 42 through the throttle check valve 48 into the chamber 85 of the hydraulic accumulator 49, and through the directional cont:,rol valve 50 into the inlet collector 59 of the controlled throttle valve 51, whence the power liquid Passes through the annular throttl,._ orifice 62 into the outlet collector 61 and further on along the hydraulic line 43 into the working chambers of the hydrostatic machine 40. When the power liquid flows through the annular, throttle orifice 62, the pressure in 16the hydraulic lines 60, 42, 56 rises and the pressure reducing valve 69 starts o~perating. Then the powexr liquid is pressure-fed through the pressure reducing valve -69 into the chamber 65 of the controlled throttle valve 51 while overcoming the force developed by the spring 71 and urge,,s the piston 57 with the rod 58 to travel to the left.

As a result, the power liquid is displaced from the chainber 64 by the piston 57 to the drainback 68, thus shutting up -the check valve 66 through the controlled throttle valve 67. Simultaneously the tihrottling area of the annular throttle orifice 62 is reduced, which increases sti,ll more the pressure in the hydraulic lines 60, 56, 42 and in the chamber 65. As the pressure in the line 42 increases the rotation speed of the shaft 44 of -the hydrostatic machine decreases, as well as that of the pinion 45 and the internal gear 29. of the planetary mechanism 24 associated with the shaft 44. As a result, the rotating planet pinions start imparting rotation, through their shafts 31, to the planet carrier 28, the hollow shaft 4 and the bucket wheel 1. At the same time the increased pressure effective in the chamber 65 urges the piston 57 with the rod 58 to move to the leftmost position, and the annular throttle orifice 62 is shut off completely by the rod 58. The hydraulic pilot Spool 55 of the hydraulic directional control valve is acted upon by the increased pressure in the hydraulic line 56 to overcome the tension of the spring, 54, thus discommunicating the hydraulic line 42 from the controlled throttle valve 51 and the pressure reducing valve 69. Hence the rotation speed of the shaft 44 of the hydrOstatii; machine 40, the pinion 45 a, internal gear 29 is reduced practically to nil, wht the rotation speed of the shaft 27 of the electric I r 23 reaches the rated value, anid the rotating planet piriions 30 impart, through their shafts :31, the entire torque developed by the drive 22 and corresponding to the Pz'eseUre effective in the line 42, to 17 the planet carrier 28, the hollow shaft 4 and the bucket wheel 1. Thereupon the power liquid pressure in the chamber 65 of the controlled throttle valve 65 drops, and the piston 57 with the rod 58 is acted upon by the force developed by the compressed spring 71 to travel to its rightmost position, thus displacing the power liquid from the chamber 65 through the throttle valve 70 to the drainback 68.

With the aforediscussed starting-up procedure of the drive 22 the forces of inertia of its flywheel mass at rest are taken up by the power liquid that circulates under a pressure gradually increasing in the a hydraulic circuit established by the working chambers of the hydrostatic machine 40, the high-pressure line 42, the hydraulic directional control valve 50, the controlled throttle valve 51 and the low-pressure line 43, which ensures against torsional deformation of the shafts 37, 26, spalling of the teeth of the pinions 25, 30, 36 and those of the gears 29, 35,as well as failure of the wheel plate 3 and the buckets 2 of the bucket wheel 1.

The acceleration time of the flywheel mass of the drive 22 depends upon the size of the throttling ar-a of the controlled throttle valve 67 and is adjustable within rather broad limits.

When the drive 22 operates under rated conditions, it is due to nonuniforn physico-mechanical characteristics of the rock being excavated and owing to the periodically varying value of the force resisting the crowding force on each of the buckets 2 of the bucket wheel 1 rotating at a rated speed, that the hollow shaft 4, the planet carriers 30, the internal gear 29 and the shaft 44 of the hydrostatic machine 40 associated with the internal gear 29 through the pinion 45, while being acted upon by the reactive torque developed by the drive 22, perform torsional vibrations which are converted in the working chambers of the hydrostatic machine 40 into pressure fluctuations of 18 the power liquid. The pressure fluctuations of the power liquid fed from the working chamrbers of the hydrostatic machine 40 to the high--pressure line 42, through the check valve 53 into the chamber 85 of the hydraulic accumulator 49 and back into the line 42 are absorbed by the gas-filled elastic diaphragm 84, and by the throttle valve 52.

Thus, when the drive 22 of the excavator bucket wheel 1 operates under rated conditions, there occurs conversion of the torsional vibrations performed by the internal gear 29 of the planetary mechanism 24 into the pressure fluctuations of the power liquid that circulates in a hydraulic circuit established by the working chambers of the hydrostatic machine 40, the high-pressure line 42, the throttle check valve 48 and the hydraulic accumulator 49, which ensures against resonance conditions at the natural frequencies of the drive 22, thereby precluding fatigue failure of the shafts 26, 37, ni-d of the teeth of the pinions 36 and those of the gears 29, Whenever the bucket wheel 1 is stopped due to suddenly increased forces resisting the crowding force of the buckets 2 to a value exceeding the motive power of the drive 22, the hollow shaft 4 and the planet carrier 28 stop rotating, while the rotating planet pinions 30 operatively associated with the electric motor 23, transmit the torque to the internal gear 29, the pinion 45 and the shaft 44 of the hydrostatic machine 40. This results in a pressure rise in the hydraulic line 42 and in the chamber of the hydraulic accumulator 49. As soon as the pressure in the line 42 becomes equal to the setting (response) pressure of the safety valve 78, -the power liquid passes from the line 42 through the safety valve 78 to the chamber 76 of the hydraulic cylinder 73 of the mechanism 41 for control over the volume of the working chambers of the hydrostatic machine 40 and, while overcoming the tension of the spring 80, the power liquid urges the piston with the rod 74 to travel to the rightmost position cor- -19responding to the minimum volume of the working chambers of the hydrostatic machine 40. Further on, the check valve 82 is closed by virtue of the power liquid prerisure, and the power liquid passes through the throttle valve 81 to the low-pressure line 43, thus establishing a closed circulation circuit. Circulation of the power liquid results in a bad reduction of the hydraulic bxake torque that has previously kept the shaft 44 of the hydrostatic machine against rotation. The shaft 44 starts rotating, thus relieving the shaft 27 of the electric motor 23 operatively connected to the shaft 44, from the torque resulting from stopping of the buckets 2 in the face.

Thus, the power drive 22 is capable of limiting the amount of power load oxi the excavator bucket wheel 1 in the case 'where the motive power of the drive 22 is suddenly exceeded by the forces resisting the crowding force, by r'educ.Jng the volume of -the working chambes of the hydrostatic maohine 40 and by virtue of the simultaneous circulation of the power liquid under a pressure limited to the setting pressure of the safety valve 78, along a hydraulic circuit formed by the working chambers of the hydrostatic machine 40, the high-pressure Llne 42, the safety valve 78, the throttle valve 81 of the throttle check va.ve 79, and the low-pressure line 43, thus preventing the buckets 2 against being broken awe.y from the wheel plate 3, as well as ensuring against developing the plastic deformation in the plate 3 and the boom 6. Than the electric 1 otor 23 is switched off, the pressure in the hydraulic lines 42, 56 and in .the chamber 85 of the hydraulic accumulator 49 decreases, and the movable components of the hydraulic directional control valve 50, those of the controlled throttle valve 51 and of the mechanism 41 for control over the volume of the working chambers of the hydrostatic machine 40 assume the position corresponding to the aforedescribed position thereof before starting the drive 22, 20 Upon rock excavation the boom 6 with the bucket wheel 1 performs angular reciprocating motion in a horizontal plane by virtue of the multiple-motor drive 21 for swinging the excavator superstructure, which drive rules out any static indeterminacy of the load applied to each of its planetary mechanisms.

The power drive 21 (FIG. 4) for swinging the superstructure 15 (IGc. 1) of a bucket-wheel excavator is constituted by three triple-link planetary mechanisms 87 (FIG. each of said mechanisms being secured on the superstructure 15, and by three electric motors 88 (FIG.4), each being held to a housing 89 of the planetary mechanism 87 (FIG. Each of the triple-link planetary mechanism 87 comprises a first link, a sun gear 90 mado integral with a shaft 91 which is connected, through a coupling 92, to a shaft 93 of the electric motor 88, a second link, i.e. a planet carrier 94 connected via a shaft to a pinion 96 which is in mesh with the gear 20 fixed in place on the crawler mechanism frame 16, and a third link, an internal gear 97 having internal toothing and arranged concentrically with the o n gear 90. The internal gear 97 is in mesh with planet pinions 98 which in turn are in mesh with the sun gear 90. The -1anet pinions 98 are fixed with their shafts 99 on the planet carrier 94. The means for protecting the power drive 21 against static and dynamic overloads is formed by the three hydrostatic machines 40 (FIG. 6) each being held to the housing 89 of the planetary mechanism 87. The shaft 44 of each of the hydrostatic machines 40 is connected, through a mechanical transmission, to the third link of the planetary mechanism 87. The mechanical transmission is made as a pinion 100 in mesh with a gear 101 Which is rigidly coupled to the internal gear 97 and is moureted on a support 102 which is located on the planet carrier 94, The pinion 100 is secured on a shaft 103 whose one end is mounted on a 4 21 support 104 and is connected, through a coupling 105 to the shaft 44 of the hydrostatic machine 40, while the other end of the shaft 103 is mounted on the support 106 of the housing 89. The similar high-pressure lines 42 (FIG. 6 of each of the three hydrostatic machines communicate with one another. The low-pressure lines 43 of each of the hydrostatic machines 40 also communicate with one another. To protect the drive 21 against static and dynamic overloads resulting from reversal of the direction of rotation of the shafts 93 of the electric motors 88, the hydraulic circuit of the drive is provided with a second hydraulic accumulator 107 hydraulically communicated, through a throttle check valve 108, with the interconnected low-pressure lines 43 of the hydrostatic machines 40, the hydraulic circuit incorporating check valves 109, 110, 111, 112 which ensure flow of the power liquid along the hydraulic lines 56 and 6U in a constant direction upon the reversal of the direction of rotation of the shafts 93 of the electric motors 88. The hydraulic accumulator 107 comprises an elastic diaphragm 113 which subdivides the interior space of the hydraulic accumulator into two chambers 114 and 115 isolated from each other. The chamber 114 is hydraulically connected, through the throttle check valve 108, to the interconnected lines 43 of the hydrostatic machines 40, while the chamber 115 is gas-filled.

The throttle check valve 108 incorporates a throttle valve 116 and a check valve 117 arranged in parallel with each other. The chambers 76 of the three hydraulic cylinders 73 are hydraulically interconnected. The intercommunicating high-pressure lines 42 are hydraulically connected to the intercommunicating low-pressure lines 43 .through the check val-'> 109, the aforementioned hydraulic directional cQntrol valve 50, the controlled throttle valve 51, and che chock valve 110, all of them being arranged in series as along the flow of the power liquid.

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22 Upon reversal of the direction of rotation of the shafts 93 of the electric motors 88, the intercommlnicating lines 43 which have become the high-pressure lines are hydraulically connected to the intercommunicating lines 42 which have become the low-pressure lines through the check valve 111, the aforementioned hydraulic directional control valve 50, the controlled throttle v.ive 51 and the check valve 112, all of them being arranged in series as along the flow of the power liquid.

The reversible power drive 21 for swinging the superstructure of a bucket wheel excavator operates as follows.

Preparatory to putting the drive 21 (FIG. 6) in operation the components of its hydraulic circuit assume the position described hereinabove with reference to the hydraulic circuit of the drive 2 (FIG,, 5) as the position before-putting the drive in operation. The check valves 109 through 112 (FIG. 6) are closed.

Upon putting the drive 21 (FIG. 6) in operation the power liquid leakage refiller 83 feeds the power liquid from the drainback 68 to the outlet collector 61 of the controlled throttle valve 51, to the chamber 64 of the controlled throttle valve 51 through the check valve 66, to the intercommunicating hydraulic lines 42 through the check valve 112, to the intercommunicating hydraulic lines 43 through the che-.k valve ,10, to each of the chambers 76 of the hydraulic cylinders 73 through the throttle check valve 79, through the check valves 109, 111 to the safety valve 78, and through hydraulic directional control valve to the inlet colloctor 59 of the controlled throttle valve 51. Thereupon the electric motors 88 are switched on. Each of the electric motors 88 imparts rotationl to the shaft 44 of the hydrostatic machine 40 through the shaft 93 (FIG. the coupling 92, the shaft 91, the sun gear 90, the planet pinions 98, the internal gear 97, the gear 101, the pinion 100, the shaft 103, and the coup-

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23 ling 105. The power liquid is fed from the working chambers (omitted in the Drawing) of each hydrostatic machine (FIG. 6) along the intercommunicating high-pressure lines 42 through the check valve 109 to the safety valve 78, 'to the hydraulic line 56 and through the hydraulic directional control valve 50 to the hydraulic line 60. As a result, the check valves 111 and 112 are closed by virtue of the pressure effective in the hydraulic lines 56 and 6C. Further circulation of the power liquid, rise of its pressure and operation of the hydraulic circuit components proceed in a way similar tO that described hereinabove with reference to opevation of the components of the hydraulic circuit of the drive 22 (FIG. 5) when putting it in operation. When the rotation speed of the shaft 44 (FIG. 3) of each hydrostatic machine 40 drops down to the ninimum value, there is decreased the rotation speed of the following components operatively associated with the shaft 44; the coupling 105, tue shaft 103, the pinion 100, the gear l10, and the internal gear 97. At that instant the rotating planetary pinions 98 imparts, through their shafts 99, the torque developed by the planetary mechanism 87 and corresponding to the pressure effective in the intercommunicating lines 42, to the planet carrier 94, the shaft 95, and tht pinion 96, While transmitting the torque of the drive 21 (FIG. the three pinions 96 roll over the gear 20, thus causing the superstructure 15 with the boom 6 (FIG. 1) to perform angular motion, which provides for feed traverse of the excavator buck~ot wheel 1 against the face in a horizontal plane.

With the drive 21 (PIG. 6) operating under rated conditions each of the electric motors 88 runs at a nominal speed corresponding to its own mechanical characteristic

W

i where w i is the running value of the angulaar velocity of the shaft 93 of the Ith electric motor 88, Mi is the torque of the ith elect-tio motor 88 cor- 24 responding to the running value of the angular velocity of the shaft 93. As a roes.lt, the shaft 44 of each hydrostatic machine 40 take up the reactive torque of its own planetary mechanism 87 (FIG. 3) imparted by the rotating internal gear 97 (FIG. said reactive torque being proportional to the driving torque of its respective electric motor 88, and rotates at the iLnimum speed in the direction of action of the pressure established in its own hydraulic line 42, thus ensuring redistribution of the reactive torque developed by the load applied to the drive 21, among the three planetary mechanisms 87 (FIG. 3) due to balancing the pressure in the intercommunicating hydraulic lines 42. In the course of convei ion of the torsional vibrations performed by each internal gew.r 97 taking up the reactive load torque developed by lis respective planetary mechanism 97, into the pressure fluctuation of the power liquid, which circulates alone a hydraulic circuit established by the working chambers of the three hydrostatic machines 40 (FIG. the intercommunicating highpressure lines 42, the throttle check valve 48 and the hydraulic accumulator 49.

Whenever the boom 6 (FIG. 1) is stopped due to the motive power of the drive 21 (FIG. 6) being suddenly surpassed by the forces resisting the boom motion in the face, there are stopped in each of the planetary mechanisms 87 (FIG. 3) the pinion 96 and the planet carrier 94 operatively associated with the pinion 96, while the rotating planet pinions 98 operatively associated with the shaft 93 of the electric motor 88 translate the toxrque to the internal gear 97, the gear 101, the pinion 100, the shaft 103, the coupling 105 and the shaft 44 of each hydrostatic machine 40. As a result, pressure is increased in the in, tercommunicating lines 42 (FIG. 6) and in the chamber of the hydraulic accumulator 49. As soon as the pressure in the lines 42 communicating with one another, becomes 25 equal to the setting pressure of the safety valve 78, the power liquid passes from the intercommunicating lines 42 through the open check valve 109, the safety valve 78 to get into the chamber 76 of each of the hydraulic cylinders 73 and causes the piston 76 with the rod 74 to travel to the extreme position corresponding to the minimum volume of the working chambers of each of the hydrostatic machines 40. Further on, the check valve 82 is closed by virtue of the power liquid pressure, and the power liquid passes through the throttle valve 81 and the open check valve 110 to the intercommunicating low-pressure hydraulic lines 43, thus forming a closed circulation circuit. Cirulation of the power liquid results in an increase in the rotation speed of. the shaft 44 of each hydrostatic machine 40, thus relieving the shaft 93 of each electric motor 88 operatively associated with the shaft 44, from the torque resulting from emergency stopping of the beam 6 (FIG. 1).

Upon reversal of the direction of the feed traverse of the bucket wheel 1 in the face, the direction of rotation of the shafts 93 (FIG. 6) of each electric motor 88 i reversed, too. The pressure of the power liquid in the intercommunicating high-pressure lines 42 and in the intercommunicating low-pressure lines 43 is hmutually balanced, and the check valves 111 and 112 ar& opened, while the hydraulic circuit components assume the position corresponding to the aforedescribed position before putting the drive 21 in operation.

The starting-up procedure of the drive 21, its operation under rated conditions and in cases where the boom 6 (PFI. 1) is suddenly stopped in the face occur in a way similar to that described above with the exception that the intercommunicating lines 43 (FIG. 6) become the highpressure lines, the interaommunicating lines 42 become the low-pressure lines, th, check valves 109 and 110 are 1- 26 closed, and the power liquid is fed from the working chambers of each hydrostatic machine 40 through the intercommunicating high-pressure lines 43, the throttle check valve 108 into the chamber 114 of the hydraulic accumulator 107.

The power drive as disclosed in the invention is most preferable to be applied to an industrial machine, e.g., to a drillrig, wherein the working element performs rotary and translational motions simultaneously in the course of drilling.

An opencast driltlrig adapted for drilling, e.g. blast holes, comprises a load-carrying structure in the form of a drill tower 120 articulately mounted on a frame 118 (FIG. 7) of a propel mechanism 119. The drill tower 120 carries a chosorail 121 provided with a feed mschanism 122 (FIG. 8) for the crosrail to traverse along the guideways (omitted in the Drawing) lengthwise the longitudinal axis of the drill tower 120. The crossrail feed mechanism 122 is made as a hydraulic cylinder 123 provided with a piston zod 124 whone ends are secuz, ed on the top and bottom girths of the drill tower 120, a tackle block constituted by four sheave assemblies 125, an axle 126 (FIG. 9) of each of them being held to the hydraulic cylinder 123, and four equal-lengtnt cables 127, each of them passing iver one of the Sheave assemblies 105 and being held with one end o the nd to the crosrail 121, and with the other end, to the middle girth o the drill tower 120.

A power drive 128 (FIG. 10) is situatod on the crossrail 121 and is composed of to triple-link planetary mechanisms 129, each of them being secured on the croesrail 121, and of two electric motors 130, each being also held to the crosrail 121. ach of the triple-link planetary mechanismo 129 comprises a first link, a sun gear 131 connected, through the input shaft made as a coupling 132, to a shaft 133 of the electric motor 130, a second link, i a planet carrier 134 which is in fact 9,

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27 the output shaft, part of the external surface of the planet carrier being made as the toothing of a pinion in mesh with a gear 135 fixed in position on a spindle 136, and a third link, an internal gear 137 set concentrically with the sun gear 131 and meshing planet pinions 138 which in turn are in mesh with the sun gear 131 and are fixed with their shafts 139 on the planet carrier 134. A means for protecting the power drive 128 (FIG. 9) against static and dynamic overloads is comprised of the two hydrostatic machines 40, each being held to the crossrail 121 and has the high-pressure line 42 and the low-pres-.

sure line 43. The shaft 44 (FIG. 10) of each hydrostatic machine 40 is connected, through a mechanical transmission, to the third link of the planetary mechanism 129. The mechanical transmission is ease.ntially a coupling 140 mounted on a support 141 which i located on the crossrail 121.

The similar high-pressure lines 42 FIG. 9 of each of the hydrostatic machines 40 communicate with each other, as well as the similar low-pressure lines 4. of said machines. The chambers 76 of the two hydraulic cylinders 73 of the mechanisms 41 for control of the volume of the working chambers of the hydrostatic machines 40 are hydraulically intercommunicating. Each of the planet carriers 134 (PIG. 10) is mounted on supports 142 and 143, the support 142 being situated in the coupling 140, and the support 143, in the crossrail 121. The spindle 136 rests on supports 144, 145, 146 aituated in the crossrail 121. One of the spindle ends is connected, through a flexible coupling 147, to a pipe string 148. The pipe string 148 is provided with a brake 149 whose brake shoes 150 are articulated to the crossrail 121, and a brake drum 151 is held to the other free end of the spindle 136. The hydraulic circuit of the drive 128 as illustrated in FIG. 9 is similar to that of the drive 21 as shown in FIG. 6, and additionally comprises the hydraulic cylinder 123 having a II 28 piston 152 which subdivides its interior space into two chambers 153, 154, and a three-position hydraulic directional control valve 155, which is hydraulically connected to the chambers 153, 154 of the hydraulic cylinder 123 and to hydraulic lines 156, 157. The high-pressure hydraulic line 156 is connected to the hydraulic line 56, and the low-pressure hydraulic line 157, to the intercommunicating chambers 76 of the hydraulic cylinder 73 of the mechanism 41 for control over the volume of the working chambers of the hydrostatic machine 40. The three-position hydraulic directional control valve 155 is provided with springs 158 and 159, and with electrically operated pilot spools 160 and 161. With the actuating element (omitted in the Drawing) of the hydraulic directional control valve 155 in the middle position, the valve disconnects the chambers 153 and 154 from the hydraulic circuit of the power drive 128. With the actuating element in the rightmost position the hydraulic directional control valve 155 connects the chamber 153 to the hydraulic line 157, and the chamber 154, to the hydraulic line 156. With the actuating element in the leftmost position the hydraulic directional control valve 155 connects the chamber 153 to the hydraulic line 156, and the chamber 154, to the hydraulic line 157.

The reversible power drive 128 of the pipe string 148 of an opencast drillrig operates as follows.

Before putting the drive 12P (FIG. 9) in operation the components of its hydraulic circuit assume the position described above with reference to the hydraulic circuit of the drive 21 (FIG. 6) when in the position before putting it in operation. The chambers 153 (FIG.9) and 154 of the hydraulic cylinder 123 alre filled with the power liquid and the actuating element of the hydraulic directional control valve 155 assumes its middle position under the effect of the forces of the springs -29- 158 and 159, while the brake drum 151 of the brake 149 of the pipe string 148 is braked by the brake shoes 150.

Upon putting the drive 128 (FIG. 9) in operation the power liquid leakage refiller 83 feeds the power liquid from the drainback 68 to the hydraulic circuit components in the same way as in the hydraulic circuit of the drive 21 (FIG. 6) when putting it in operation. Thereupon the electric motor 130 is switched on, the shaft 133 of each electric motor imparts rotation, via the coupling 132, the sun gear 131, the planet pinions 138, the internal gear 137 and the coupling 147, to the shaft 44 of the hydrostatic machine 40. The working liquid starts circulating along a hydraulic circuit made up of the working chambers of each hydrostatic machine 40, the intercommunicating high-pressure lines 42, the check valve 109, the hydraulic directional control valve 50, the controlled throttle valve.5 1 the check valve 110, and the intercommunicating low-pressure lines 43, the check valves 111 and 112 being in this case closed. An increase of the power liquid pressure in the aforedescribed hydraulic circuit and the operation of the hydraulic circuit components occur in the same way as described above with reference to the operation of the' hydraulic circuit of the drive 21 (FIG.6) when putting it in operation. However, the pressure in the intercommunicating lines 42 rises at the instant when the rotation speed of the shaft 44 of each hydrostatic machine 40 drops down to the minimum value, while the rotation speed of the shaft 133 of each electric motor 130 reaches the nominal value. When the pressure in the lines 42 gets equal to the settling pressure of the safety valve 78, the power liquid is fed from the lines, 42 through the check valve 109 and along the hydraulic line 156 to the hydraulic directional control valve 155, and throg4h the.safety valve 78, is admitted to the chamber 76 of each hydraulic cylinder 73 and, while overcoming the 30 tension of the spring 80, urges the piston 75 with the rod 74 to moveto the hottommost position corresponding to thG minimum volume of the working chambers of each hydrostatic machine 40. Simultaneously, the working liquid pressure causes the check valve 82 to close, and the working liquid passes through the throttle valve 81 and the check valve 110 into the intercommunicating low-pressure lines 43, thus establishing a closed circulation circuit. Qirculation of the power liquid results in an abrupt reduction of 'the hydraulic brake torque that keeps the shaft 44 of each hydrostatic machine 40 against rotation. The rotation speed of the shaft 44 of the hydrostatic machine 40 increases to -the value corresponding to the nominal ro~tation speed, of the shaft 133 of the electric motor 130 opera' ively associated with the shaft 44. Then the electrically operated spool valve 161 is put in operation and, while overcoming the- tension of the spring 158, the spool valve causes the actuating element of the hydraulic directional control valve 155 to move to the leftmost position. The hydraulic directional control valve 155 connects the chamber 153 to the high-pressure hydraulic line 156, and the chamber 154, to the low-pressure hydraulic line 157, whereupon the hydraulic cylinder 123 of the crossrail feed mechanism 122 starts travelling with respect to the piston rod 124. As a result, the volume of the chamber 153 increases, and 'the volume of the chamber 154 decreases, while the sheave assemblies 125 and the tackle block cables 127 passing over the sheave assemblies move the crossrail 121 with the drive 128 and the pipe string 148 along the guideways of the drill tower 120 towards the hole bottom. In the course of the aforementioned travel of the pipe string 148 towards the hole bottom the pressure in the hydraulic line 156, in the intercommunicating lines 42 and in the hydraulic line 56 drops below the setting pressure of the safety valve 78, the latter disconnects 31 the chamber 76 of each hydraulic cylinder 73 of the mechanism for control over the volume of the working chambers of the hydraulic machine 40 and the hydraulic line 157 from the hydraulic line 56. The pressure in the hydraulic line 157 and in the chamber 76 of each hydraulic cylinder 73 decreases, and the piston 75 with the rod 14 is urged by the force of the compressed spring 80 to move to the topmost position corresponding to the maximum volume of the working chambers of each hydrostatic machine 40. The rate of feed of the pipe string 148 towards the hole bo,tom depends on the throttling area of the throttle 81 of the throttle check valve 79. The pipe string 148 stops as soon as it reaches the hole bottom.Then the pressure in the chamber 153 of the hydraulic cylinder 123 starts increasing, as well as that in the hydraulic lines 156, 56, 42. As soon as the pressure in the hydraulic line 56 becomes equal to the setting pressure of the safety valve 78 the power liquid is fed from the lines 42 through the check valve 109 and the safety valve 78 into the chamber 76 of each hydraulic cylinder 73 and, while overcoming the tension of the spring 80, urges the piston 75 with the rod 74 of each hydraulic cylinder 73 to travel to the bottommost position corresponding to the minimum volume of the worklin chambers of each hydrostatic machine 40. Then the breake shoes 150 are disengaged from the drum 151, thus releasing the brake 149 of the pipe string 148. The pressure in the intercommunicating lines 42 decreases. As soon as the pressure in the lines 42 drops below the setting pressure of the safety valve 78, the latter disconnects the chamber 76 of each hydraulic cylinder 73 and the hydraulic line 157 from the hydraulic line 56, and the piston 75 with the rod 74 is actuated by the force of the compressed spring 80 to move to the topmost position corresponding to the maximum volume of the working chambers of each hydrostatic machine 40. When the volume of the 32 working chambers of each hydrostatic machine 40 is increased from the minimum to the maximum value, the hydraulic drag torque increases, too, thus reducing the rotation speed of each shaft 44 operatively associated with the internal gear 137. As a result, the rotation speed of the internal gear 137 of each planetary mechanism 129 is reduced to the minimum value, Then the rotating planet pinions 138 impart, through their shafts 139, the torque of the drive 128 to the planet carrier 134, the gear 135, the spindle 136 and the pipe string 148. The pipe qtring 148 (FIG. 9) gains its rated speed of rotation, and the pressure in the chamber 153 of the hydraulic cylinder 123 which corresponds to the pressure in the intercommunicating hydraulic lines 42, provides for the nominal feed rate to the pipe string.

When the drive 128 (FIG. 10) of the pipe string 148 operates under.rated conditions, static indeterminacy is ruled out in each of the planetary mechanisms 129 similarly to the drive 21 (FIG. 6) described above. The drilling rate and the force of feed of the pipe string 148 (FIG.9) depend on the throttling area of.the throttle valve 81 of the throttle check valve 79. The energy of torsional vibrations performed by the internal gear 137 of each planetary mechanism 129 (PIG. 10) is absorbed by the hydraulic circuit described above with reference to the drive 21 (FIG. 6) when putting it in operation. The same hydraulic circuit absorbs the energy of pressure fluctuations in the chamber 153 of the hydraulic cylinder 123 hydraulically connected to the intercommunicating high-pressure lines 42 through the hydraulic line 156 and the open check valve 109.

Whenever the pipe string 148 (FIG. .10) is stopped due to the motive power of the drive 128 having been suddenly exceeded by the forces resisting the rotation of the pipe string 148, there are also stopped the spindle 136, 33 the gear 135,. the planet carrier 134 of each planetary mechanism 129, while the rotating planet pinions 138 operatively associated with the shaft 133 of the electric motor 130 transmit the torque to the internal gear 137,the coupling 147 and the shaft 44 of each hydrostatic machine As a result, the pressure in the intercommunicating lines 42 (FIG. 9) and in the chamber 85 of the hydraulic accumulator 49 increases. Further rise of the power liquid pressure and the operation of the components of the hydraulic circuit of the drive 128 occur in the sanme way as described above with reference to the hydraulic circuit components of the drive 21 (FIG. 6) in the case of its sudden stop.

When the direction of rotation of the pipe string 148 (FIG, 9) has to be reversed, which is the case when the pipe string is to be broken, the electrically operated spool valve 161 of the hydraulic directional control valve 155 is turned out, and the shafts 133 of each electric motor 130 are reversed. The actuating element of the hydraulie directional control valve 155 is urged by the force of the compressed spring 158 to move to the middle position. The hydraulic directional control valve 155 disconnects the chambers 153 and 154 of the hydraulic cylinder 123 of the crossrail feed mechanism 122 from the hydraulio circuit of the power drive 128, and the crossrail 121 is held in place with respect to the drill tower 120 in a position corresponding to its position at the instant when the el,4ctrically operated spool valve 161 has been turned out. The pressure of the power liquid in the intercommunicating lines 42 becomes equal to that in the intercommunicating lines 43, the check valves 111 and .12 get open, while the hydraulic circuit component assume the position corresponding to the above-described position of the components of the drive 128 before putting it in operation. Putting the drive 128 (FIG. 9) in ope-

J,

34 ration upon reversal of the direction of rotation of the pipe string 148 and its operation durirng the breaking of the pipe string occur in the same way as described above with reference to the starting-up procedure of the drive 128 with the exception that the brake 149 of the pipe string 148 remains released, and the intercommtvuicating lines 43 become the high-pressure lines, the intercommuniating lines 42 become the low-pressure lines, the check valves 109 and 110 get closed, and the power liquid passes from the working chambers of each hydrostatic machine through the intercommunicating high-pressure lines 43, the throttle check valve 108 into the chamber 114 of the hydraulic accumulator 107. The energy of power liquid fluctuations resulting from an abrupt increase of the pressure in the intercormiunicating lines 43 upon undoing the components of the pipe string 148 being unbroken, are absorbed by the gas-filled elastic diaphragm .113 of the hydraulic accumulator and by tho throttle valve 116 of the throttle chock valve 108.

When extending the length of the pipe string 148 the electrically operated pilot spool 160 of the hydraulic directional control valve 155 is turned on, and the brake drum 151 of the brake 149 of the pipe string 148 is braked by applying the brake shoes 150 thereto. The actuating element of the hydraulic directional control valve 155, while overcoming the tension of the spring 159, travels to the rightmost position, and the hydraulic directional control valve 155 comrunicates the chamber 153 of the hydraulic cylinder 123 of the crossrail feed mechanism with the hydraulic line 157, and the chamber 154, with the high-pressure hydraulic line 156. Thereupon the hydraulic cylinder 123 starts travelling with respect to the piston rod 124, with the result that the volume of the chamber 153 decreases and the volume of the chamber 154 increases. As a result, the sheave assemblies 125 and the tackle block 35 cables 127 passing over the shea' e assemblies move the crossrail 121 with the drive 126 along the guideways of the drill tower 120 away from the hole bottom. In this case the shaft 44 of each hydrostatic machine 40 rotates at a speed which corresponds to the nominal rotation speed of the shaft 133 of the electric motor 130 operatively associated with the shaft 44. The travelling speed of the croesrail 121 depends on the throttling area of the throttle 81 of the throttle check valve 79.

Hydraulic communication between -the chambers 153 and 154 of the hydraulic cylinder 123 of the crossrail feed mechanism 122, made according to the invention, affords protection of the feed mechanism 122 against static and dynamic overloads under rated drilling conditions and in the case of emergency stopping of the pipe string 148 due to the motive power of the drive 128 being exceeded by the forces resisting the pipe string rotation, which reduces pressure fluctuation and limits the maximum pressure of the power liquid in the hydraulic cylinder 123.

Industrial Applicability Used as a power drive of the working element of an industrial machine can be an electric otorboth variable and constant speed, I.O.ogine, steam power machine or any other prime mover.

However, most promising is the application of an electric motor in this particular case, as such a motor provides all favourable properties inheent in a volume-type hydraulic drive, while its service life is comparable with that of an electromechanical drive.

The drive is assembled of standard elements, is rather inexpensive in manifacture and does not require much time for assembly purposes.

WVhenever necessary the proposed drive can be transformed nearly instantly into an electromechanical drive by disconnecting hlydraulic elements therefrom.

©1 36 The present drive can operate in conjunction with any number of prime movers having any total power output.

The present drive is especially efficient when used for industrial machines subjected to high alternating loads featuring high dynamic factors, such as, for instance, minehaulage machinery, drillings, excavators, crushers.

The present invention features the following advantages: freedom from double energy convertion, inherent in a hydratlic drive; direct saving of hydraulic power under rated conditions up to twofold; considerable increase in the service life (upto 30 or thousand hours of continuous operation, With the filtration rating of the power liquid UP to 10 Lm).

The present drive has been employed in a drilling as a power drive for a drillrod string and has demonstrated practicability of all the advantages mentioned above, high service durability, high safety and adjustment properties, reduced torsional and vertical vibration of the drillrod string, and higher durability of a bit.

Claims (7)

1. A power drive of the working element of an industrial machine, situated on its load-carrying structure, incorporating a multiple-link planetary mechanism having a gearing arrangement adapted to take up the reactive torque developed by the planetary mechanism, the input shaft of the mechanism being connected to the shaft of an actuating motor, the ptoer drive having an output shaft operatively 10 associated with the working element of the machine, and a means for protecting the power drive against static and dynamic overloads, characterized in that the means for protecting the power drive against static and dynamic overloads is in effect a hydrostatic machine held to the load-carrying structure of the industrial machine and provided with a high-pressure line and a low-pressure line, the high-pressure line and the low-pressure line forming part of a hydraulic circuit, a shaft of the hydrostatic machine being connected, through a mechanical transmission, to the gearing arrangement of the planetary mechanism that is adapted to take up the torque developed by the mechanism. 5 9 S 0 S. Ss""

2. A power drive of the working element of an industrial :'0ooo machine as claimed in claim 1, characterized in that the high-pressure line of the hydrostatic machine is connected to a hydraulic accumulator through a throttle check valve, and is connected to the low-pressure line through a hydraulic directional control valve and a controlled throttle valve, both being arranged in series in the direction of the flow of power liquid in the hydraulic circuit.

3. A power drive of the working element of an industrial machine as claimed in either claim 1 or claim 2 characterized in that the hydrostatic machine is provided V with a mechanism for control of the volume of the wor'*ng Schambers of the hydrostatic machine, the mechanism ,ng LS 7 81774S/SLT s 4 38 made as a hydraulic cylinder held in position inside the housing of the hyd ostatic machine whose chamber at the end of a rod is hydraulically connected, through a safety valve, to the high-pressure line of the hydrostatic machine, and through a throttle check valve, to the low-pressure line, while a chamber of the hydraulic cylinder located at the end of a piston is provided with a spring whose one end is connected to the barrel of the hydraulic cylinder, and its other end is connected to the piston, the chamber being communicated witi a drainback.

4. A power drive of the Vorking element of an industrial machine as claimed in claim 3, characterized in that it is ge provided with at least a second multiple-link planetary 15 mechanism whose input shaft is connected to a shaft of a second actuating motor, while its output shaft is operatively associated with the working element of the industrial machine, while a second gearing arrangement of the second planetary mecanism that takes up the reactive torque developed by the ter mechanism, is connected, through a mechanical tY. .~'.ssion, to the shaft of a second hydrostatic machine vFhich ieS held to a load-carrying structure of the indt' machine, the hydrostatic machine Scomprising the high-p.assure line hydraulically connected to a C 25 the high-pressure line of the first hydrostatic machine, a low-pressure line hydraulically connected to the low pressure line of the first hydrostatic machine, and a second Smechanism for control over the volume of the working S chambers of the second hydrostatic machine, the second 30 mechanism being made as the hydraulic cylinder fixed in position inside the housing of the first hydrostatic machine, the chamber of the hydraulic cylinder located at the end of the piston is provided with the spring whose one end is connected to the barrel of the hydraulic cylinder, and its other end is connected to the piston, which chamber is communicated with the drainback, while the chamber y'v' located at the end of the rod is hydraulically connected to i 1774S/SLt 39 the chamber located at the end of the rod of the hydraulic cylinder of the mechanism for control over the volume of the working chambers of the first hydrostatic machine.

5. A power drive of the working element of an industrial machine wherein provision is made for a mechanism of feed traverse of the working element as claimed in claim 4 characterized in that the mechanism of the feed traverse of the working element is made as at least one power cylinder operatively asscoiated with working element and fixed on the load-carrying structure of the industrial machine, the power cylinder having at least two chambers wherein one of the chambers of the power cylinder is hydraulically communicated with the high-pressure line of one of the hydrostatic 15 machines, while the other chamber is hydraulically connected to the chamber located at the end of the rod of the S" hydraulic cylinder of the mechanism for control over the volume of the working chambers of the same hydrostatic machine.

6. A power drive of the working element of an industrial machine substantially as herein described with reference to the accompanying drawings. l** DATED this 13th day of September 1990 e MOSKOVSKY GORNY INSTITUT By their Patent Attorneys GRIFFITH HACK CO. 81'/74S/SLT

7 A' ditionally comprises the hydrrulic cylinder 123 having a 43 POWER DRIVE OF THE WORKING ELEMENT OF AN INDUSTRIAL MACHINE Abstract of the Disclosure A power drive of the working element of an indust- rial machine is located on its load-carrying structure (6) and incorporates a multiple-link planetary mechanism (24) and an actuating motor The input shaft (26) of the mechanism (24) is connected to the shaft (27) of the ac- tuating motor, while the output shaft is operatively associated with the working element of the machine. Provision is made in the power drive (22) of the machine for a means to protect the drive against static and dyna- mic overloads, which is made as a hydrostatic machine made fast on the load-carrying structure(6) of the indust- rial machine and provided with a high-pressure line (42) and low-pressure line The shaft (44) of the hydro- static machine (40) is connected, via a mechanical trans- mission, to the link (29) of the planetary mechanism (24) which is adapted to take up the reactivs torque developed by the mechanism.