US2620629A - Hydraulically-operated crusher of reciprocating type - Google Patents

Description

K. GAULDIE Dec. 9, 1952 HYDRAULICALLY-OPERATED CRUSHER OF RECIPROCATING TYPE Filed Aug. 10, 1949 Patented Dec. 9, 1952 HYDRAULICALLY-OPERATED CRUSHER F REGI-PROCATING TYPE Kenneth Qauldie, Toronto, Ontario, Canada Application August 10, 1949, SerialNo. 109,551

In Great Britain November1 7,-l948 V a c im (Cl. 60 5.4.5)

The present invention relates. to hydraulically nperatedcrus'hers of the reciprocating jawv type in.:which energy .is transmitted. .to the reciprocating :sjawthrougha ram.v to which. pulsating pressure applied. and .is primarily concerned with means for compensating. for leakage past the ram. or .lelsewhere in. the hydraulic system, with the object of maintaining constancyof the limitsibetweenwhich the jaw normally operates.

In. :cmsh'ers of the closed-'hydraulic-system itype iitis necessary-to add liquid to the hyrdaulic system as leakageioccurs from it; otherwise-the volumezof .liquid in. the system. would diminish, the .zreciprocating. member would oscillate between-receding limits, and the mean. opening between the jaws...w0uld.increase. Means to this endwhich has previously. been proposed comprises a stcp againstwhich the ram-contacts towardsthe end. ofits return strokeandwhich consequently defines .thebackward limit of movee ment-offthe-swing jaw. In consequence .of the leakage which :occurred in the preceding cycle of operation, the ram and jaw ;are arrested before theplunger by which they :pulsating pressure is developied,...hasreached the end of its-induction stroke. A sub-atmospheric .pressure is come.- quentlysdeveloped :inrthe hydraulicsystem during the remainder of. the. induction stroke of the plunger, .and liquid enters theisystemthrough an automatic. :valve. in .amount. equal to the leakage which occurred during :thepre'ceding. cycle. This method is open to the-objection that, .if leakage should :bev appreciable, the momentum. of the massive moving parts. attheinstant of th'eirarrest mightbe large and might. involve heavy blows on the stop. Ina hydraulically-operated crusher. a relief valve to protect the structure againstvdamage by. tramp steel caught between the jaws 'wouldxnormally be provided, and .it is when the .relief valveoperates for this. or .other reasonthat the. above mentioned objection appliesin thehhighest degree. In. such case, the leakage from the systemduring a working stroke might belhalf the displacement of the plunger. On thesucceeding return stroke, the heavy jaw and ram .wouldbearrestedwhen moving at'their maximum velocity; the. corresponding blow would: be heavy and might be; destructive.

According to the method employed in the present invention, make-up liquid, under the control of-external regulating means, enters the hydraulic system at mean rate equal to the mean rate at which leakage occurs from the system. In the embodiment described with reference tothe accompanying drawings, make-up liquid enters the hydraulic system from an external sourceof pres.- suregthrcugh avalve, the opening through which is so;controlled by the movements of thereciproeating jaw or associated part that the average rate of. inflowof make-up liquid into the hydrauno system is equal to theaverage rate of leakage from the system. The volume of liquidin the hydraulic system is .thereby maintained constant and, without the useof any mechanical stop a definite range; of movement of the oscillating jaw is maintained and allpossibili-ty of dangerous impact is avoided.

Referring to the drawing, Fig. 1 is a viewsome what diagrammatic and partly .in cross-section illustrating my invention, and Fig. 2 is a longitudinally cross-sectional view of a valve used in Fig. 1 and onan enlarged scale compared to Fig. 1. Referring to Fig. '1, I have shown a jaw crusher lfljhaving afifixed jawll and a movablejaw l2 .mountedion apivot [-3. The swing jaw I2 .is moved inits crushing stroke toward the fixed jaw. H by means of a ram M in a hydraulic chamber I-5.; A :plunger l6 which may be reciprocated by any suitable source of power through a crankshaft 16a. and connecting rod H alsooperatesin the hydraulicsystem to drive the ram; "The return stroke of the jaw 12 is caused by .gravityand' the action of the spring -Ila held in compression between adetent. Hand an abutmntj38' acting on the rod. [8' which is connected-to the .lower end of the movable jaw. Leakage pastthe. plunger [6 and the ra'mltis conducted byjthe pipes 19 and 20 to a sump 2 f. Make-upffiuid is d'elivered by a pump 22 from the sump -2. l' ltoltlie'hy'draulic chamber 2 I5. through .a valve 23. The detentf24 is mounted on and movable with the rod lflland may be adjusted along the rod by a nut.- 2'5. The detent 24 carries "a tappct 26 in a position whereby it may engage the stem 2. 1 of the valve 23.

"The valve 23;,as illustrated in Fig. .2 comprises a regulating needle 28 which is freely movable in theclosingdirection and a dashpot which consstrainsthe needle to move slowly in the opening direction. The dashpot comprises a piston 30 on which thevneedle 28, is mounted, a. spring 32 which tends to .move the piston and needle in the opening direction, channels 33. communi eating between the two sides of the piston and a valve 34,;of the non-return type, for example .a disc valve which normally closes. these channels.

when -a. force. in excess cit-the tension o-fithe spring 3211s applied to the. end of. thevalve spindlexZil liquid isdisplaced past the disc valve 34 *ircm. one side of the piston 30 to the other the hydraulic cylinder.

In the normal operation of the crusher, make-y up enters the hydraulic system only during the return strokes of the ram l4 when thepressure in the system is low; and it is only. againstthe;

l valve 36 is shown between the needle valve and low pressures then existing thatqthe make-up pump 22 must be designed to discharge. Under these conditions the non-return valve 36' permits "past the ram l4 and plunger i6 under any 'c-onditi'on'of normal operation of"'-the--crusher. -If the make-up pump is of positive displacement til-De its surplus capacity is by-pas'sedthrough'relief valve 31 and is normally used for the lubrication 'or the plunger-crankshaft and other bearingsand is returned ultimatel'y' to' the sump 21. Anynecessary cooling 'system'maybe-incorporated in the circuit or" the 'make up'fpump.

when'the crusher isin normal operation the tappet 26 barely touches the endofthe spindle 2;} at the limitof-"the forward stroke of the former and moves the needle'28-slightlyin the closing direction. "Free fo-rwardmovementof the needle valve is permitted by the disc 'val've'34 which permits free passage of liquid from left to rightof the piston 30 throughfthe-ports 33 whenpressure in excess of the tension ofthe opr posing spring 32 is applied to the'end off'jthe spindle 21'. At allother times'theneedle moves slowly in the opening direction, the rate'of speed being determined by' the leakage whi-ch'takes place past the piston 30 or'tl rough a'res'tricted aperture especia'lly'provided in'the disc valve 134'. The mean position of thene'edle and'the mean rate at which liquid can enter the'hydr'aulic sysg tem are, therefore, determined by the location of the tappet when at-the forwardlimit 'o'fjits'stroke and by' the "slight distance throng-hf which the needlemoves-in the opening direction during the remainder of the period of oscillation of the tap pet." Y As the valve spindle is touchedby'the tappet several times a second the position of thenee dle is practically fixed" in'relation to the position of the t'appet and of the swing jaw at the forward limits-oftheir strokes; T ,:-Let it bea'ssumed for purpose of explanation that during a period of shut-downof the crusher, liquid has leaked from the hydraulic system so thatthejawhas'swung back from its normal setting and that, under 1 these conditions; the

orusher'isstartedup. "In this assumed case'th'e needle valve 28 is wide open'and the flow through it exceeds considerably the rate at which leakage o-ocursrfromi the hydraulic system; With every stroke of the crusher thevol'umeof liquid inthe 4 hydraulic system, therefore, increases and the ram and the swing jaw oscillate between advancing limits until, after a short period of operation, the tappet 26 at the limit of its forward strokes contacts the end of the valve spindle 21 and moves the needle 28 step-by-step in the closing direction until the normal position previously describ ed iis attainedg that is, the: position at which 'theiate 'of make-up inflow is 'throttled into equality with the rate of leakage. After that condition has been established the volume o f liquid in the hydraulic system remains almost constant and the ram and swing jaw oscillate between fixed limits. -If under'operating condition the needle valve .23 s-houldhavajoeen moved slightly too far by -the ,tappet 26 at the end of the stroke of the latter the rate of make-up inflow into the hydraulic system is reduced to slightly less than the rate at which leakage occurs from the system. The swingjawwconsequently tends tooscillate between receding limits and at the end of the .next stroke contact between the 'tappet 26"'and the valve spindle- 1 2 l is not established? Th wneedlea 2.8, therefore, continuesito move in the opening direction during the succeeding; stroke .andany. slight increase in the close'setting ofsthe jaws which maylh-ave occurredi in any stroke is correctediin the-succeeding strokes. 1 A similar'correction 'oc-'- ours in the reverse. direction if the rate'ofleakage should "be less than the rate at which make -up can enter through the valvev23. The swingj'aw is-consequently constrained by the systemtobscillate between limits determined by th'e position o'ffthe valve needle 28" at which". equilibrium be tween'leakage'andmake-upoccurs; If I the-- setting of the tap pet 2 6* is moved relative to the swin jaw thelimitsbetween' which the latter oscillates will be: changed; -If, fo'r'-ex'- ample, thetension-wod-nut 25 is"screwed to move in a dire'cti0n away from:the jaw,"the tappet zli will move back with the-'nut 25' andit will not contact the valve "spindle?! at the end 'of =its immediatelysucceeding strokes? Theneedle valve 28 aspreviously describediwill" continue to move. in" the :opening. direction and inflow of make-up in excess' of leakage would occur and the swing jaw and ram would oscillate between advancing:- limits until, after a :few strokes, OOH: tactbetween the tapp'et 2li-and' the valve. spindle 2 1" had. been reestablished}: Thereafter-, the' jaw would continue to oscillate: between fixed-limits at a closer setting-than before. iSimilarlyl i-fithe tension.- rod nut'25is moved 'forwardon'the rod 18 toward the jaw, the corresponding movement ofthe tapp'et will. resultin a wider setting of the jaw 'opening. :Theimounting Ofut'hfi tappet on the outer'end of thetension rod provides,stherefore, a simpleand convenientmeans' whereby the setting OfZ'thE swing jaw may be adjusted. It will be noted that innormal operation-the positionin'.spaceaof the. tappet 26 atthe end 0f its-forward stroke, is. determined by th'e" position of the valve needle :28 at.which-equilibriumbe tween leakage andmake-uphcciirs'; 1 That is, the location of thetap'pet at the f orward end 'of'its stroke is fixed relation tothe framef of th'e machine That definite. location" ofth'e tappet isytherefore, fixed in relation to th eimierabutmemes ofthe tension rodsp-ring.

It 'fbllOWS that, aftl" anjadjllStIl'l'Iltd-f th'jaw settinghas been made, the negrmrwonme length and tension of ithe tensioh rod sp rin g l'ld are automatically reestablished and that ho sep'a rate adjustment of'this' tension'is required after m-hdiustment cf jaw setting hasbeen 'made; tension of springiis iietcrmined by its working length which; in turngis determine-d iby the-='location of the tappet 2 6 at the end of its forward "stroke, in relatio'nto the equilibrium position-"of the valve-spindle "2 1. vittuis, therefore, adjustable-by 'appropriate changein thatirela'ti-ve position-: For purposes'of tension spring" adjustment, the tappet 26' ma'y'a's indicated in 1-, bd inoun ted for a. *screw adjustment-on the defiant-24.

If the tappet 26 is adjusted in a b'ackwar'd- :di.- rection relative to the detent 2'4, equilibrium between leakage and make-up will not be reestablis-hetl until the detent, atthe forward limit ofl-its I stroke; hasmoved-an equal distancein the' r'evers'e direction-i Backward adjustment of the' tappet relative to the-'detent on which iti's mounted-has; therefore, the effect 'oi shortening the working. length of the tension-spring i121 and of increasing its me'an tensi'on. reward adjustment of the tappet dias the-" reverse effect, and'it is primariily with the ob ject of adjusting the tension of the spring l m that tappetadjustment is provided.

longitudinal adjustment of the tappet ha's' also' the' e'flec't'of changing the jaw setting by equal amount; and minor adjustments ofja'w setting may be efiected in this manner. It will also b evident-that i'f an axially adjustable anvil were provided on the end of the valve spindle 21, adjustment of jaw setting could be eiiected by corresponding axial adjustment of the anvil along the spindle 21 without stopping the *ma'chine. Spring tension would, however, be changed by movement of the 'anvil and this method is, therefore, more particularly applicable for minor-setting adjustments which it may convenient to marewnenthecrusheris in'oper'ation. 1 i i relief valve would normally 'be included in the hydraulic system-ofthis or any hydraulically op'ra-ted jaw crusher asa protection-against damage by tramp steel, or other uncrushable obstruction caught between the jaws. It is one of the advantages of a crusher made according to this invention that a relief valve provides such protection and also provides for automatic ejection of the obstruction and for subsequent automatic reset of the jaw opening.

When the swing jaw and ram are arrested by tramp steel, liquid escapes from the hydraulic system through the relief valve. On the succeeding return stroke of the plunger 16 the swing jaw I2 moves back beyond its normal limit and permits the obstruction to descend in a hopper. On the next active stroke of the plunger the jaw is again arrested and the relief valve again operates and more liquid escapes from the hydraulic system. On the next return stroke of the plunger the swing jaw moves still further back and the obstacle descends still further in the hopper. This process proceeds until the obstruction reaches the outlet and is discharged. The system then continues to operate in a manner which has already been described in connection with the starting up of the crusher after a shut-down to bring the swing jaw automatically to its normal setting.

While I have described my invention applied to the control of the jaw movement from the closed setting thereof, it is apparent that it may be controlled from other settings. For example the operation of the jaw may be controlled from the open setting. In this case the needle valve could be of the normally closed type and if moved in the opening direction by a tappet when the swingj aw Li's 'at the backward limit o-f'its return stroke --:and if the valve at 1 other times-" tentls to close, its controlling operation wouldbe essentially-ithesameas that of the valve illustrated' -in Fig.-2. 1

If the 'rangeiofoscillation of the-swing'j aw-were controlled from=lthe backward limit ofithe oscil lating'parts specialmean's would, however, here'- qttiredto' permit th'e swing jaw to :movebacklbeyend'A-that limit when freeing itself from -tramp iron. For this and other practical reasons com trol for -the range. of "oscillation of the-jaw ironi thetforward limit: :of its reciprocating movement is mechanically simpler and is preferred.

According to the latter 'method (that is, ac' cording to the invention as illustrated-in the drawing) the valve imposes no restriction-whatever onthe backwardmovement ofthe jaw and, in normal operation, alt-offers no material restrain't on forward movement of the jaw. It might occur; I however, that with the crank 4 5d; at top centre; th'etappet ZBmig-ht'beadjusted into contact with the valve spindle '2-1' and thatthe crusher might then be started. In such case damage wouldoccur if'the valve spindle' werenot freeto-move througha distance equal to the complete stroke of 'the tappet.

For that reasori the diame'terof the outlet port 39, of the valve illustrated in fig. "2, sl-i-'ghtly exceeds thediameter of the -needlep the length' of the port-exceeds the stroke of'the' tappet'ahdthe valve is htherwise --designed to permit an -axialmovementof l the 1 valve spindle in excess of v the stroke of the-tappet.

What I claim as new and desire 'to' se'cure =by Letters Patentor the Unitedfi'tates is? l. In a crusher having a reciprocatable jawQa ranr-cylinden 'and a raw in the cylinder, a -hy-* draulic system Tor-operating the jaw to produce crushing; strokes thereof comprising "power transmitting liquid in the 'cylinderf'and means for-adding make-up liquid to the system to' c'ompensate for leakage from it comprising an external source of liquid at a pressure higher than the minimum pressure occurring in the ram cylinder, means forming a liquid passage connecting said source with the ram cylinder, a valve controlling liquid fiow through the passage, said valve including an element movable to control said liquid flow, and a member mechanically connected to the jaw and operable thereby to move said element.

2. in a crusher having a reciprocatable jaw, a ram cylinder, and a ram in the cylinder, a hydraulic system for operating the jaw to produce crushing strokes thereof comprising powertransmitting liquid in the cylinder, and means for adding make-up liquid to the system to compensate for leakage from it comprising an external source of liquid at a pressure higher than the minimum pressure occurring in the ram cylinder, means forming a liquid passage connecting said source with the ram cylinder, a valve in the passage, said valve having two elements, one of said elements being relatively movable with respect to the other to adjustably control flow of liquid through the valve, and a member mechanically connected to the jaw and operable thereby to move said one of the elements.

3. In a crusher having a reciprocatable jaw, a ram cylinder, and a ram in the cylinder, a hydraulic system for operating the jaw to produce crushing strokes thereof comprising powertransmitting liquid in the cylinder, and means for adding make-up liquid to the system to compen'sate..-for leakage from: it "comprising ant-ex!- ternal source'of liquid at a pressureihigher than the minimum pressureoccurring in the ram -cyliinder,: means forming asli'quid passage connecting said source with the ram cylinder, an adjustably movable valve vin the passage controlling-flow of liquid ,therethrough, said valvehavirig a portion fixeditheretmand extendzexternally of the; pas-f sage,- saidportion v being movable :with theiuvalve to adjust: the position thereof, and; a. member connected-to the,;jaw and: reciprocal therewith, said' member being, in" opposed, disconnected-relat tion, to: saidgvalvefl portion andgsaid-valve- :Ipor: tion being :engageable, by said member {on ad justmentin one direction; thereby gonlywwhen the jaw isisapproaching-palimit of eacnuofsits crushingstrokes t. v a 1;. w 4. A crusher as defined ,inkclaim; 3,;saidvmem-v oer comprising a tappet,- a vreciprocally.;-;mounted rod carrying said gtappet; said rod-having a &piv.- otal connection ;with the, j aw; and means, urging the latter and said rodin a;.-directiona opposit to-, the. di1ection-;0f saidcrushing strokes. 1. V. A: crusher asdefined'tin-claim-53;,=said valve being v reelyi movable in one directiony resilient means, "for moving.: said valve, in its oppositewdi rection, and dashpot means iforgrestricting 'toia slow ;-rate;;th e movements of saidavalve. inits oppositedirection; a I H -6 .;In;.a crusher having a. reoiprocatable jaw; a ram cylinder and .a. ,ramin ;the.=cylinder-,=:;a hydraulic system for operating the jaw to sproduce crushing strokes thereofcomprisingv powere. transmitting liquid in the cylinder -andmeans for adding mak eeup liquid to the system to compensate for leakagetherefrom comprising amex-ii ternal source;,-f make-up;tliquid-yata pressure higher than the minimum pressure ocourring; -in ther m cylinder, means f m a li uid passa connectingsaid source"with theyram QYli Ad- IJ, 4

valve vvmeans in the passage for controlling flovv of, liquid ,therethrough and having an opening;

s a valve .zmovablei to close and openv said opening said valve: being freely movable inwone, direction, resilienttmeansurging the valve in-,its opposite direction;- said valve; shaving. I va I: POflilOIl=yfiX6d theretoj and extendingexternally.Qfthe pas age; a member connectedto ,thez jaw and ;;reciprocal therewith,'.-said; member being in opposed,-;dis oonnect'ed', relation I: to {said valve; portion and; said valve portion :being engageable by said/member, for movement in SELid-J- one 1 direction; only :when the jaw is approaching a limit of each of -its crushing-fstrokesw it; 51-; 'j'; "A crusher, as; defined; in ,claim '6, herein said :resilient means comprisesa pistonon which saidevalvejis mounted, a resilient element engag ing'xoneeend cit-he,- piston; and urging gitj in; said opposite; direction of; the; valve, means forming a 'liquidl passagei communicating-with both ends of said piston, and -a;;one-,way' valve -;control1ing liquid;flo.w.throughsaidipassage. ,4 i A crusher 'as defined in rcla-im;.6, i--wherein said: resilient means comprises; a piston 1 on :which said :valve .1. is; mounted, :a. resilient, element engaging; one; endof the iston ;;and-- urging; it in said opposite direction of thej valve,- said" piston havingas liquid passage extending ,in an axial direction;,therethrough; andrla one-way valve controlling; liquid flow throughsaid passage a; i KENNETH .GAULD E...

s l The following-references "are of recordin th fii offihi Patntt-1--* I v um er; 2Qfl84- v:

- Mar;- 9,;1875 July-1 22, 1913 une. 9 1 ,Ma 2,; 9: 3

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