CA1271109A - Power unit - Google Patents

Abstract

POWER UNIT

ABSTRACT OF THE DISCLOSURE

Disclosure is made of a power unit wherein a housing is made split along its longitudinal axis. A
tubular elastic vessel is internally coaxially accommo-dated in the housing. Disposed between the expandable portions of the housing: are expanding inserts trape-zoidal in section, bearing by their larger bases against the tubular elastic vessel and by the sides, against the inner walls of the housing portions. For delivery of a working medium into the space of the elastic vessel provision is made for two pipe unions, each of which is installed for longitudinal movement in a holder having a flange disposed in a circular recess made on the inner surface of the housing, An elastic element surrounding the elastic vessel is in-stalled in the same circular recess. Each of the elastic vessel ends is disposed between the pipe union and the holder.

Description

~2~ 9 Th~ pre~ent i~v~lbioll relabs~ t~ ~he mi~lng ang~-~e~rlng ~d, m~ra ~p~cific~ , b~ a po~er u~ib f`or de~trucbion o~ rooka.
~i~Ld o~ ~h~ InY~nt~D~
~h~ pr~s~nt i~lV~lltiD~ be u~ or breakl~3 off l8r~ rock ms~oliths along ~he llae ~f bla~thole~
~011D~q~d by di~i~te~r~ti~ of monolitb~ intD block3~
*or explosi~ ~r~e dri7 ing of rock worki~g , ~or d~truc-tio~ D:~ found~tiD~ sf old buildi~gs ~d oth~r ~tron~
10 ~ootings. W~ be powe~ uait is used i~ borehole~
b~ ~mplD~e~ ~or vvsakeni~g ~ difficult-tD-col-lap~e roof in minlLg Df th~ ~txatified deposlb~, for .
p~si~lve deg~sicg o~ coal 3~ 1, for ~racturl~g of r~ervoir~ and g~3-b~ari~g ~trat~, f~r ~ud,~iQg the 15 ~tres~ed a~d de~rmed sb~te ~f a rock ~ u~dor natu-r~l c o nd it ion~ .
The pre~ent 1~venbiD~ be us~d in ths metal- :
worki~g lndustr,~ as a pswer~ul ~ slze drive ~or a~tuat~ne m~a~ of pro~es9 j~ck~, guillotine~ a~d obher i~3tallatiDn9 utllizl~g cDnsiderable diractcà
orce B~ckground D~ o I~enti~
En~w~ he prior ~rt is a power u~it: (cf. USS~
von~or's Ca~bi~lca~e ~o"420,779, cl, E 21c 39/00~ 1974), ; ~ 25 c~mpri~1~g ~ h3usi~ ter~allg accDIQmod~ting alD~g the ~: :

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longitudinal`axis and throughout the entire length thereof a tubular elastic vessel with sealin~ means dis-posed at the ends thereof. The housin~ of the given power unit comprises two portions one of which is stationary rclative to the axis of the power unit, while the other one is an extendable metal plun~er.
,'Yhen pressure i~ the hydraulic system is raiSed the inner space o~ the elastic vessel is filled ~ith a working medium and the vessel is expanded. ~s the volume occupied by the elastic vcssel is restricted by the housinæ portions, the plun~er extends and acts upon an ob~ect.
The po~Yer unit develops the force in a present direction proportionally to the area of the plun~er surface in contact with the elastic vessel, Thus the erficiency of the power unit o~ the above-mentioned design is low.
"ie understand the efficiency as a ratio between tha force developed by t~e po-~er unit in a preset di-rection and the l~orce developed by the elastic vessel~The transverse coml~onent of the wor,{ln~ ~edium pl'~S-sure built up by the elastic vessel, the vector of which is perpendicular to the vector of the force developed by the power unit in the preset direction is not utilized for developin~ the ~oree in the preset direction. The transverse co~ponent causes

- 3 ~27~ 3 de~ormation o~ t~e stationar~ portion of the hous-: in~ bri~ging about ther~in plastic strains which reduce the reliable operation o~ the power unit.
When pressure o~ the working medium in the elastic 5 vessel is raised, it i~creases the value o~ the trans-: verse co~ponent. Increase o~ the transverse co~ponent causes ~or~ation o~ clearances 'between the plun~er and the stationary portion of th~ housing in which : the material Or the elastic vessel "~'lows". ~his con-dition leads to rupture, i.e. to depressurization o~
the elastic vessel. The ways for improving rigidity o~' the hou~in~ le~d either to an increase in t'he metal content or to a substantial complicatio~ of the power unit manu~acturin~ methods on the whole, Attempts of increasing the ef~icie~cy o~' the power unit ~ave rise to the construction disclosed in : USSR Inventor's:Certificate No.19033,819, cl.E21C
.~ 37~06, 19~2.
q'he known power unit comprises a longitudinally ; 20 split housin~ intarnally coaxially accommodating a tubular elastic vessel and two expanding inserts, each o~ which is disposed on the side o~ the parting line ~ o~:the housin~. :In the plane perpendicular to the : ~ housin~ axis:tcle insert has a trapezoidal section :
the larger base o~ ~vhich be~rs a~ainst t~e elastic : vessel~acld the sides bear against the inner wall of : ~

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the housin~. In a~dition, the power unit incoFporates two holders each of which is provi~ed with a pipe union intended for delivery of a worXing medium into the space of the elastic vessel. Each of the ends of the elastic vessel is disposed betw0en the pipe union and the holder. A perfor~ted tubular core is arranged in the space of the elastic vessel alon~ the longitudi-nal axis thereo~. Each end of the perforated tubular COl`e i9 made in the form of a pipe union. ~ach of the holders is essentially a sleeve wita the in-ter~al thread en~aged with the e~ternal thread of the pipe union; thus the hol~ers are riiOidly connected -w-ith each other through the medium of the perforated core.
The nol~ers are intended for sealin~ the ends of the elastic vessel.
when the ~iorkin~ medium is delivered under pres-; sure into the inner space of the elastic vessel the ~ housing portlons are ex~anded both by the elastic :
vessel and the expandin~ inserts.
~ he lcnown power unit f`ailed to find wide appli-cation in breakin~ natural rock monoliths, for example, grani~e~ of* the~roc~ mass~because of a limited force developed by -the elastic vessel, for exampl~, about 10 MPa, as the po~er unit cannot dev210p the reguired force in the preget direction, i.e. in the direction ; ;perpendicular to the pl~ne of t~le breaX. '~his is ~; ~

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explai~ed by that the substantial axial loads aris-ing in the tubular core stretch it. 1~is l~ads to formation of a clearance between the end of the hous-ing and the end of each of th~ hol~ers facin~ the elas-tic vessel. '~he material of the elastic vess~l "flows"in this clearance and then the vessel ruptures~ ~esid~s~
t~le core stretching weakens the sealin~ of the elastic vessel ends which brin~s about leaks of the working medium. '~he core stretching may be reduced at th~ cost of increasing the core cross-soctional area. However, it leads to a sharp increase in the overall dimensions and metal content of the power unit, or in case of maintaining the original overall dimensions of the po~er unit it brin6s about a decrease in the working : 15 travel of the housin~ movable portions and a rise of -~ the unit pressure at the;place where the slde surface : of the inserts come in contact with the inner surface of the housin~ which is not desirabl2, as it involves : the use of special m~terials and lubricants.
It should also be not~d that the trapezoidal shape of the~ex~andin~ inserts is not optimum, as in case of a non~uniform Oearin~ of the housin~ expandable portions against th~ ~surface o~ a blasthole or a bore-:: hole, a clearance is formed between the side surface o~
~each insert and the inner sur~ace of the housin~ in which the material o~ the elastic vessel will 'rflow ~.

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, :: ~ . . - . . . . -7~ )9 Summarg of the Invention It is an object o~ the present invention to widen the field o~ the power unit application at the expense of a substantial increase in the force exerted by said unit in a preset direction by way of raising the p~essure of the working mediu~ in the elastic vessel, with retention of the preset overall dimen-sions and reduction o~ the po~er unit metal content.
It is another object of the present invention to improve reliability of the power unit operation by way of transmitting t~e tens1le ~orces set up in the elastic vessel to the ex~andable portions o~ the hous-ing and by compeasatin~ ~or microclearances ~orrQed at - high pressures.
It is still another object ol the pr~sent inven-tion to improve r~liability o~ the sealing of the ::~ elastic vesse} ends by way of clampin~ thera on the pipe unions with a ~orce proportional to an increase : in the pressure of the working medium in the ~l~s-tic ~;~ : 20 vesselO
o accornplish the fore~oing and other obaects, the invention consists ln that in a l~ower unit co~p~
rl~in~ a longitudinally split iaousing internally coaxia-accornmodatinæ~a tubul~r elastic vessel~ two : : 25 expanding insert each of which is disposed on the side of the housing parting line and has in the plane perpendicular to the housing axis a trapezoidal 7 - !

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section the ~reater base of which bears against the elastic vessel, While the sides bear ~ainst the inner wall o~ the housing, two holders eacn of which is provided with a pipe union intended for delivery o~
a ~orkin~ medium into the space o~ the elastic vessel, each o~ the ends of the el~stic vessel being disposed betwee~ -the pipe union and the hol~er, according to the invention, ~ch of the hol~ers has a fla~ge dis-posed in a circular recess ~hich is made~on the inner surface o~ t~e nousin~ and accoml~odates an elastic element surroundin~ the tubular elastic.vessel, and the pipe unions are i~stalled in the holders ~`or lon~itudinal movement.
Such a~ embodiment o~` the power unit widens the field o~ its application, for example, i~ explosion-free breaking o~ large hi~h-strength natural roc~
monoliths ~rom the roc~ mass, ~or ~ract~uring boreholes - :
in the rock mass with the aim o~ evaluating the stressed state of the earth's crust, preventing the 2Q: rock bursts, etc. '~his is achieved by increasing the maximum directed f:orce de~eloped by the power unit due to~the ~âct that the axial ~orce being essentially a lon~itudinal compone~nt of the ~orking medium pres-. sure in the elastic vessel is ta~en up by the hous-2~ 1ng of the power unit. '~his has beco~e ~easible due ; : to arran~ement of e~ch of the hol~er fla~es in a .
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~ 9 circular recess made on the inner wall o~ e~ch of the split housin~ portions. Now the housin~ o~ the power unit is capable of takin~ up substantial axial forces, ~s its cross-sectio~al area considerably exceeds the 5 cross-sectional area of the power unit tubular core disclosed in US~R Inventor's Certi~icate No.1,033,819.
'~nis improved the longitudinal rigidity of the power unit which ~ade it possible to diScard the tubular core, reduce the metal content a~d to Simplify the power unit manu~acturin~ methods. As in the process of the ~ower unit ope.ration the s~lit portions of the housin~ take up substantial axial ~orces, the power unit construction is ~ade prestressed. This e~cludes plastic deformations in the housing which impro~es re-liabilit~ and durabilitg of tne power ~nit~ Due to an increase in the lon~itudinal rigidity of the power unit; reli~bilit~ oY its operation at considerable rise o~ the workin~ medium pressure in the elastic vessel is ~ proved ~ as tha ~icroclearances between the housing and fla~es o~ the holaers appearin~ at hi~h pressures are ~iecreased. In addition? these microcleara~ces are compensated for by expansion of the elastic elements surrounding tha tubular elastic vessel~ each of` the el~stic elements being irst~lled in a circular recess made on the inner surface o~ the housing, Each of the el~stic ele~e~ts is in contact with the face o~ the holder, the surf`ace o~ the circular recess and with - . ~., .
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the ~ace of the expanding insert. '~his prev~nts the material o~` the el~stic vessel ~rom "flowln~" in the clearances and -thus substantiall~ impro~es relia-bility of tne po~er unit operation at high pressures, ov~r 100 i.~a, o~ the workin~ medium in the elastic vessel, ~ he power unit may advantageously be provided with two bushin~s eac~i of which is rigidly connected Wit'.l the holder and has a central cylindrical passa~e for receiving the pipe union, conjugated with the co-nical sur~ace ~vhose ~eneratrix has an angle of incli-nation relative to the lo~itudinal axis of the bush-in~ correspondin~ to the an~le of incli~ation of the generatrix o~' the conical surface o~ the pipe union head, and the ~eneratrix of the conical surface made in the holder has an a~le o~ inclination relative to the lon~itudinal axis of' the holaer corresponding to the angle o~ inclination of the ~ensratrix of another : conical surf`ace of the pipe union head~ with the co-nical sur~aces of the bushin~ and the holder facing each other by the lar~er bases.
~ urina assembly of the power unit the ends of the elastic v~ssel are clamped between the appropriate.
conical surf~ces. ~,ihen the workin~ medium is delivered un~r pressur~ throu~h the pipe union into the in~er space of the elastic vesssl, the ends thereo~ are , _ 10 ' .. ' ', ' '.

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ad~itionall~ self-sealed, as the pipe union is adapted for lon~itudinal movement within the limits ~overnecl by the el~sticity of the material o~ the elastic vessel. It should be noted that the greater the pressure in the inn~r space of the elastic vessel, the stron~er is the clamping o~ the ends thereof bet--ween the conical sur~ce of the pipe union head and the respective conical surface in the inner sp~ce o~
the holder. 'l'his makes it possible to avoid depressuri-10 ~ation o~ the elastic vessel space at hig~h (of theorder of 100 ~,~a) pre~sures and hence to increase the force developed b~ lhe po~er unit. 'nhus, the reliability of sealin~ o~ the elastic vessel ends is improved due to their clamping on the conical surface of the pipe union head witil a force proportional to an increase of the workin~ medium pressure in the elastic vessel, Preferably, each o~ the elastic elements is made in the form of a cone-shaped ring, is installed in a conical recess provided in the end portion o~ the holder ~'la~ge and bears by its base ~gainst a washer installed in tho circular recess of` the housing.
Embodiment of the elastic elements in the ~orm of cone-shaped rin~s allo~s the wedge effect to be employed for transferring the forces to the washer which in the process o~ the power unit operation covers an annual microclearance between the holder ~lan~ and ''' ' ' ' .' :

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the ~ovable parts of the construction. This takes place due to the fact that the cone-shaped rings are capable of radial expansion and bear by their bases against the axially movable washers made~ for example, of m~tal. ~pansion of t~e tubular elastic vessel causes a defini-te radial expansion of the cone-shaped rinOs ~ihich b~ their bases force the washars against t.,e faces of the housing split portions and t`ne faces of tae ~x~anding inserts, thereby co~pensating for the annular ~icroclearances ~ormed at high pressures and thus prevent the material o~ the elastic vessel from "flowin~" in said microclearances~ ~his substantially il~proves reli~bility of tne po~er unit operation.
The power unit according to the inve~tion has found v~ide a~plication in dif~erent branches of the industry, for exa~ple, in mining en~ineering and construction:
- for rock quarrying by ~ay o~ breaking lar~e ~onoli-ths alon~ the line o~ blastholes o~f the roc~
mass followed by disintegration of monoliths into blocks;
- for explosion-free driving of mine workings (tunnels, adits, etc.) When a~plication of the blast-ing operations is not per~issible;
25 l ~ ~or destruction of strong lootings and foundat-ions of old buildings;

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for cleaning up slopes in constructio~ o~
roads, water ~evelopments and other objects under conditions of mountainous t~,rrain;
~ for WeaKening of a difficult-to-collapse roof;
- ~or forced degassi~g of coal seams and preven-tion of instantaneous outbursts by ~ay of a positive relie~ of sea~s;
- for fracturi~g of strata in oil and gas holes;
- ~or stuaying deformation and stren6th proper-ties, and the stressed state of a rock mass of any strength in boreholes at a preset depth.
: ~a~ing into account its compactness, power and : : 15 hi~h r~liability, the po-~ier unit according to the ve~tion is used i:n the machine-building and metal-working industries as:a universal driv~ of directed action ~or:
powerful;presses a~d press tools (providing both unil~teral and alL-round reduction) witn a totaI
orce of ap lOO,OC0 t and upward;
powerYul jaCL~s~ ln t.iose cases wLlen there is no need for a:substantlal working travel;
- guillotlnes used for cutting sheet steel, wire ropes,:chains and other materials.
The power unit:acc~ording to the invention shoY.,s promise ~or use in actuating me,ans of industrial ro~*s.
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Brie~ Description of Drawing~
Additional objects and advantages o~ the inven-tion will appear fro~ the follo~ing description in wnich the pre~eIred embodiment is set forth in detail in conjunction with the acco~p~nying drawi~s, viherein:
~ig. 1 schematically illustrates a power uni~
according to the invention, in a cut-av~ay view;
Fig. 2 is e section on II-II o~ Fi~ 1, reYolv-ed 90.
A po~er unit according to the invention desi~ned, for example, ~or roc.{ guarryin~ by ~Jay o~ bre aking lar~e nonoliths alon~ the lina of blastholes off the rock mass followed by disinte~ration of monolithS into : 15 blocks 9 comprises a lon~itudinall~ split housing 1 (~ig. 1~ coaxiall~ accommodating a utubular elastic vessel ~. ~nds o~ the~elastic vessel are put on pipe : : unions 3. Eacn of the ends o~ the ~lastic vessel ~ is secured betwéen a holder 4 provided with a ~lange 5 ~ : 20 and a bushin~ 6. '~`tliS bushin~ has a cylindrical pas-: : sa~e ~or receivin~ t'ae :pipe union 3, conju~ated with a conical surface -~.;Lose ~eneratrix has an an~le o~
inclination relative to:the lon~itudinal axis o~ the bushing 6 correspondine to the angle of inclinatio~ of ~:::: 25 the ~aneratrix of the conical sur~ace o~ the head of : the pipe union 3, and the generatrix o~ the conical :: . , 14 _ :

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surface made in the holder 4 has an an~le of` inclinati-on relative to the lon~itudinal axis o~ the hol~er 4 corr~sponding to the angle of` inclination of the generatrix of another conical surface of the head of`
the pipe union 3, ~ith the conical surfaces o~ the bushing 6 and the hol~er 4 f`acing eac~l other by the larger bases. The ends o~ the tubular elastic vessel 2 are clamped between the conical surfaces o~ the head of' the pi~e union 3 and the bushing 6 by means of a nut 7 and a w~sher 8. 3isposed on the side of the parting line of the housing 1 are expanding inserts 9 (~ig. ~), each of which in the plane perpendicular to the housing axis has a trapezoidal section. Inserts 9 : bear ~ainst the tubular elastic vessel ~ through 15: liners 10 m~de of an elastic material. M~de on the end surf&c~s o~ the flanges 5 (Fig. 1) are conical reces-ses which accommodate elastic elements made in the f'or~
of co~e-shaped ri~gs 11 bearing by their bases against ::
as'aers 12. Elastic rings 13 surrounded by ri~id limit-ing rin~s 14 are:arran~ed in tne circular grooves pro-vided on t~le outer surf`ace of` the housing 1.
he power unit operates in the ~ollowing wa~.
Whe~ the working medium is delivered throu~h the pipe union 3 into t~e inner s~ace of the tubular 25~ elastic vessel ~, the latter expands; in this case, ~ ~ :
~ the force is transmitted to the split portions of : .
~ the housing 1 bot:-l by the tubul~r elastic vessel 2 ~:
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and the expandin~ inserts 9. Under the action of the Working medium pres~ure in -the inner space of the elastic vess01 2, the pipe union 3 moves in the lon-~itudinal direction within the limits governed oy the elasticit~ o~ the material of the el~stic vessel, there~y ensurinO the self-sealin~ o~ the elastic vessel ends. It should be noted that the greater the pressur~ of the workin~ medium in the space of the elastic vessel, the stron~er is the clamping of the ends thereof between the conical surface of the head of the ~ipe union 3 and the respective inner conical surface of tne holder. This ma~es it possible to avoid depressurization of the elastic v~ssel 2 at àign pres-sures o~ aboat 100 lmPa. l'he pressure of the wor~ing 15 m~dium is tra~smitted through the tubular elastic ~;vessel 2 to the c;one-shaped rings 11 and caus~s an :~ : elastic e~pa~sion of the l~tter in th~ radial directi-o~; as a result, the cone-shaped rin~s 11 force the ashels 12 ~gainst:th~ f`aces o~ the expandin~ inserts : ~20 9 and against the side su~face of tae circular reces-ses on the inner surface of the housin~ 1, in ~hich the holders 4~are ri~idly ~ixed a~ainst lon~itudlnal displaceme~t. ~hls compensates for the annular micro-: clearances for~ed at high pressures, thereby prevent-ing the material of tne elastic vess~1 2 from "flowi~g"
:: in t'ae ~icroclearances. ~iihen the working pressure is :reduced to zero~ all the movable elemsnts of the ~, ~
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power unit return to the ori~inal position un~er the action o~` the elastic rinæs 13 which tnrust against the rigid limiting rings 14.
~rhe use o~ t'ne ~iven po~er unit makes it possible 5 to subs tantially step up the labour productivity in yuarrying and processin~ of the building stone, improve the sa~ety and to simpli~y the tecnnology of some un-der~round minin~ processes. '~he use ol the po~er unit in the machine-building and metal-working in-dustries as a po~erful drive ~or actuating means ofpresses and jac~s ~a~es it possible to ~implify the construction and to reduce~the overall dimensions thereo~.
: The economic e~iciency of' the invention has been considered o~ a speci~ic e~bodiment thereof in-tended f`or use in one o~` the application Ylelds.
A power unit manu~actured accolding to the pre-sent invention Y~ith a len~:th o~ 40 cm and outside dia-meter ;o~ 42 mm develops a f'orce of` 300 t at a pres-sure o~ the workln~ medium in the elastic vessel equalto 100 l~a waicn ~llo~Ys it to be used as a working ; : m~ns ~`or brea~ing of'f the roc~ monoliths alon3 the line of`:blastholes.~

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Claims (4)

The embodiments of the invention in which an exclu-sive property or privilege is claimed are defined as follows:

1. A power unit, comprising:
- a longitudinally split housing;
- an inner wall of said housing;
- a tubular elastic vessel coaxially accommodat-ed in said housing;
- an inner space of said tubular elastic vessel;
- an outer wall of said tubular plastic vessel;
- two expanding inserts, each of said inserts is disposed on the side of the parting line of said hous-ing and in the plane perpendicular to the longitudinal axis of said housing, and is trapezoidal in section the larger base of which bears against said outer wall of said elastic vessel, while the sides bear against said inner wall of said housing;
- two pipe unions intended for delivery of a working medium into said space of said tubular elas-tic vessel;
- two holders in each of which is installed one of said two pipe: unions adapted for longitudinal mo-vement;
- two ends of said tubular elastic vessel each of which is disposed between one of said two pipe unions and one of said two holders;
- two circular recesses made on said inner wall of said housing;

- a flange of each of said two holders arranged in one of said two circular recesses;
- two elastic elements, each of which surrounds said outer wall of said tubular elastic vessel and arranged in one of said two circular recesses.

2. A power unit according to Claim 1, comprising:
- two bushings, each of two said bushings being rigidly connected with one of said two holders;
- a head of each of said two pipe unions formed by two conical surfaces;
- a central cylindrical passage conjugated with the conical surface for installation of one of said two pipe unions, made in each of said two bushings, a ge-neratrix of the conical surface has an angle of in-clination relative to the longitudinal axis of one of said two bushings, corresponding to the angle of incli-nation of the generatrix one conical surface of said head of one of said two pipe unions;

- a conical surface made in each of two said hol-ders and directed by its larger base towards the conical surface made in each of said two bushings;
the generatrix of said conical surface has an angle of inclination relative to the longitudinal axis of one of two said holders corresponding to the angle of inclination of the generatrix of another conical surface of said head of one of said two pipe unions.

3. A power unit according to Claim 1, comprising:
- a washer installed in each of said two circu-lar recesses;
- a conical recess made in the end portion of said flange of each of said two holders and intended for internally accommodating one of said two elastic elements made in the form of a cone-shaped ring bear-ing by its larger base against said washer.

4. A power unit according to Claim 2, comprising - a washer installed in each of said two circular recesses;
- a conical recess made in the end portion of said flange of each of said two holders and intended for internally accommodating one of s aid two elastic elements made in the form of a cone-shaped ring, bear-ing by its larger base against said washer.