US2333487A - Centralizer for rock drills - Google Patents

Description

Nov. 2,v 1943'. P. H. NAsT cENTRALIzER FOR ROCK DRILLs 3 3 sheets-sheet 2v Filed Sept. 22, 1942 INVENTOR 19u/L H. A4452 BY v Patented Nov. 2, 1943 l ff UNITED srAfrEs Rar-'Enr OFFICE I 'n Passaic? A v .CENTRALIZER Fon ROCK DRlLLs frnuln. Nasepetrda, Mich., assigner to. 'chicago' Pneumatic Tool Company, TN'ewfYok, "N. Y., a .corporationl'of New Jersey "Applicationseptember z2, 1942, 'seri-.t1 m4459259 l.'Zlhis invention relates` tocentralizer 1 apparatus ofthe kind provided in rockdrills of the drifter type to guidethe .drill steel when starting. ahole. vIn a drifter the .drillis `supported ona shell mount and advances relatively .thereto `as it drives the .working steel vthrough .the rock. The [steel Y ordinarily is supportedand .guided .only by .the chuck yparts ofthe drill. 'This does .notmake for an alignment .suiiciently rigidtofprevent thesteel from being deflected .out of. its proper .course when starting a hole inan irregularsurface.A As a-re sult'it is the practicet'o attachtothefront of the 'shell an auxiliary guide means ori centralizer which furnishes a bearing for .thesteel in ad- -vance of ther drill. According v.to Athepreferred construction of a centralizar it lcornprisesessentially4 a pair of guide' ,arms :supported V.oni a f body portionfor pivotalmovement tdand-.from a position in which they combinesubstantiallyitosurround `the vdrill'stel with'a closeft. Movement 'of the centralizer arms" from .effective positionis necessarykinV Order not to restrict the advance .f the drill and is generally accomplished'byA the drill itself which vrocks the` arms out of 'its .path

after a travel suiiicient Itostart the .steel along;

justment. v

.The present invention contempla-resa centralizer construction which is broadly new although;

retaining the essential elements. and'general mode of operation'r of prior. art devices. j

One object of the invention .is to makepossible a more positiveontrol o'f the centralizer arms.

Another object is to. simplify vthe 'structure o'f the .centralizerounit through a reduction `in the numberof parts, while makinguse o'f'a 'construction lending ruggedness andllong life` to" the unit. 'A further object 'of th'einventionis'to 'embody inthe centralizer anoil'reservoir and ports "leading therefrom tofriction bearing surfaces intthe unit; vfor purposes tof lubrication.

Incarrying out these "Objects a drillsteel'centralizer has resultedwhich comprises 'aibddyhaving a projecting stub-shaftand abore constituting an oil'reservoir, a-'guideplate'and atrunn'ion 5 plate slidably mountedon the shaft, centralizer arms pivotally mountedvon angularly 'disposed trunnions on the trunnion plata-reaction surfaces on the guide plate-against which f'theiarms bear in 'pivoting on thetrunnioniplata'fcams effecting position of adjustment.

.companying drawings, wherein:

i jOther.objectsandstructural details ofthe invention will.beapparent from the Vfo1lowing..de

scription when fread in. conjunctionwith the acvthearmsfin full linesas theyappearwhen closedv to .effective position` and `in dotted .lines .as they .appear 4when' opened .to i ineffective position;

Fign`2 is-a viewlike Fig. .1 but inside elevation; l-Fig.l`3 .is a fragmentary verticallongitudinal .sec-

.tiontakenthrough the .body portion, showingthe oiLreservoir and communicating ports;

.Fig ..7 iis-;a-.detail.view,l.in perspective, of .the

trunnionplate; and L, I l

z Figs. -.8 :to .11are..detail views of rone of the centralizar-arms, t1i!ig.:],0 being in cross-section :takenalongthelineiD-lof Fig9. l l"Referringffto Figs. .1v1-and 2, fragmentary-portions-of `tlfre-drillfthe working-steel, and the vshell .mount are-indicatedl respectively at v2i), -2 I and 122. Alsoeshownnis 'apart of thefeed screw 23, -this being arotatable screwthreaded shaft extending .lengthwise --of -the vshell and operatively `-engaged with #the .drill --tol `advance-and retract it towardandrfromfthe-work. n

Cenventionallyfthefront of-th'e shell 22 is closed .by an:end=.p1ate providinga bearing for'the front of the feed -screw.f23'.- Invthe present'instance, this.-plateis-embodiedin an element 24 which serves also `v`as Ithesupport-.orslcnody portion of the 'drillnsteel'ceritralizenv The 'body 24 is fastened :to thefshell by f through side rods y25, and, midway .betweenthe rods ata ypoint aboveits central'axis, is :formed *Withia -bore T26 adapted to receive Athe 'end'of l:thefeed screw `23:-(see Figs. 3 and 6,) A bushing 21 'in thefbore'formsthe `bearing surface within-which'the: screw rotates. c f

'Projectingfforwardly lfrom y'the 'fbody porti-on '24 lis-an integrally formed'stub shaft "23. Sur- -mouting the rstub AAsl'iaft `arev control yelements z of the '.'ceritralizer assembly, includingja 'combina'- tionguidefandreaction plate' 29 and y:a'trunnion plate 31.' 'The plate 29occupie's .the inside poe sition ron-the fsh'aft28 abutting afb'oss 3l) on l'the vfront face of the body 24. ^In jorder Vtol position vthe guide plate '.rotatvely, ia recess 40 isV formed ftherein adapted `to vregistery with the bor'e '26 'inlthe'body-ll. As vshow'n-inlig. 3, the recess T4@ "drill, 'angular jaws 36 on thei plate 29, and, in crossaction plate 29.

closes the bore 26 at the point where it breaks through the body 24, and receives the inner end of bushing 21 which thus acts as a dowel pin. The trunnion plate 3| lies in front of the plate 29 and, as shown in Figs. 5 and '7, has flat side surfaces 50 inclining rearward and inward toward the axis of the shaft 28. Oppositely disposed trunnionsj32 wextend at right angles from the surfaces 50 and therefore at any oblique angle with respect to each other and to the longitudinal axis of the trunnion plate. ring to Fig. 4 the trunnions 32 are surrounded by bushings 33 and provide a pivotal mounting for centralizer arms 34. As shown alsoin Figs:v

8 to 11 the centralizer arms curve upward and inward from their base portions 34a toward the axis of the drill steel andterminate in concave surfaces 35. of the separate arms provide a restricted passage for the drill steel, preventing its departure from thel longitudinal line defined by the axis of the The base portions y34|@ are embraced by section, have a rect'ai'igularV shape,V the sides "thereof paralleling the respective sloping surfaces 50 of the trunnion plate ,3|. The jaws 3S prevent the centralizerarms from slipping off thehtrunnions 32 and furtherare of aidV in holding the armsflrmly against the drillsteel. In the plate 29 at ,the base of eachjaw 36is formed a groove 3'! in which the edge of the associated vcentralizer farm is engaged( `to prevent `rotary movement of the trunnion plate. The bottom of the groove is flat and complementary surfaces are formed on the edge of the lcentraliser `arm (see Fig. 9), these surfaces beingindicatedY at 38 and 39 connected by a rounded area 4|.

Ysteel and drops the arms outof the path of the drill. In the upright closed orfeffective position ofthe arms vthe'surfaces 381 thereon are presented tothe guide plate 29 while movement to ineffective position brings the surfaces 39 to cooperative relation withVK the guide plate,A withr the area 4| acting as a camion the plate to enforce an axial movement ofthe trunnion plate 3 The plate 23 thus acts as a reaction element against `which the centralizer Varmsbear as they are set to pivotal positions of adjustment.

The parts are controlled and held with the arms 34 in closed or open positions by a spring assemblysurrounding the shaftl 28 in front of thetrunnion plate 3|. "I'he 'assembly comprises a single spring 42 interposedbetween vrespective front and rear washers 43 and 44. The washer 43 functions as a base for the assembly, being held against axial movementalong the shaft by a two-piece ring 45 placed ini a circumferential grooveV 46 in the 'outer end of the shaft 28. The washer 44 presses Vdirectly upon the trunnion lplate. 3| ina direction to maintain the centralizer arms in contact with the guide or re- Thus, in rocking about their pivots to` and from' drill guiding positi0n,`the

`centralizer arms are opposed by the spring 42.

The spring yields as the trunnion plate 3| is cammed forward ,in response to the turning of the arms and then presses the yparts back to normal as the rounded areas 4| pass themid- Together the concave surfaces 35` Refer-Y point of their motion along the reaction plate. The spring 42 acts yieldingly to maintain the arms in their effective or ineffective positions. It is thought that the use of one large spring for positioning the centraliZer arms is -an improved construction, as compared with the small spring plungers and detents ordinarily used for this purpose.

The construction of the centralizer apparatus permits self-lubrication of the friction bearing surfaces therein. To this end a central bore 4l is formed in the shaft 2S of the centralizer body, which bore functions as an oil reservoir. Lubri- `eating oil is'introduced into the reservoir through l a registering 'plug screw 4S in the plate 29.

a filler fport 48 V(see Fig. 3), normally closed by A port 5| conducts oil from the reservoir to the bore 26 and recess 46 where the end of feed screw .23 isjournaled. A series of ports 52 (see also Fig. y 4) radiate from the reservoir andopen,to theA exterior ofthevshaft at a point surrounded by the@ trunnionplate 3|. The bearing surface upon which the trunnion plateslides is thus subject to continuous lubrication andthe movement'of the centralizer arms to and from effective position Ais unhindered. The Asurfaces of the'trunnions 32 receive oil through passages 53 in the trunnion plate, which passages register withV the ports 5 2 at one ,point of the arm travel fromclosed to'open positions. i y

VInassembling the centraliser, the body portion 24iirstis"secured to thefront of the shell mount.

22"brytl'ieside rods 25,'lwith theend of the feed screfw K23 resting infthebre 26. Then the plate 23 isfslipped overthestubshaft 23 and moved rearward thereon. Therecess 4|lis aligned with the b ore `2 6 andl is fitted on Ato the combination bushing'and V clovvelpin Y2, -as the. guide plate enlgages the-boss 30. The trunnionV plate 13|, with the two armslv34inr place on theutrunnionsw, follows the guide platefon the shaftA 28, and the lovvezredgesoff the centralizerarms are inserted in the grooves 31.

The spring :assembly comprising springllzand Washers43 and 44 is then mounted 'ontheouterl end of the body and locked in k placelbyfthe' ring,.45. ThepressureY ofthe spring," as exerted through the trunnion plate 3|, holdsfthewrcentralizer arms engaged in the gro`ovesv3'l Wand: resists turning movement of the arms "around, the trunnions 32. A capScrew 54 closesV the" front ofthe reservoir bore 4l, and may be usedin conjunctionfwitha suitable yoke to compress thespring 42' to permit removal of the ring 45. .j Y

Preparatory to startingA adrilling operation the arms 34 "are adjusted to their upright or closedposition where they guide the drill steel as'it begins formation of the hole. As drilling progresses the drill advances relatively tothe shellgand thev centralizer and, when the centralizer arms 'have accomplished their function of directing the steel'through the desired course Following retraction of the drill the arms may be returnedto upright position by-hand and so rendered effective againrto guide the drill Steel.

- What isclaimed is: A r

l; A drill steel `centralizerV forv a rock drill adapted to advance -longitudinally during operation, comprisinga body portion, a, trunnion plate supportedby -said bodyfor'movement relative thereto, -means causing the Vmovement of said trunnion plate fto occur in a direction substantially parallel with the longitudinal axis ofjsaid "reges-354s? trunnion I plate and Vag'aii'rs arms bear inpivoting on sai'dipl'a'te, -andspring means *urgingsai'd trunnion plate in a direction substantially parallel with the longitudinal axis of said drill in order to press said arms against said reaction means.

3. A drill steel centralizer according to claim 2, characterized in that said spring means comprises a coil spring surrounding said stub shaft exteriorly of the trunnion plate.

4. A drill steel centralizer, comprising a body portion having a projecting stub shaft, a plate slidable on said shaft, trunnions on said plate angularly disposed with respect to each other and to said shaft, centralizer arms pivotally mounted on said trunnions, stationary angled jaws serving to guide said arms and having reaction surfaces against which said arms bear in pivoting on said trunnions, a plurality of angular faces on said arms brought selectively into cooperative relation with said reaction surfaces by pivotal movement of said arms, spring means urging said trunnion plate in a direction to press said arms into said angled jaws and thereby maintain said arms yieldingly in any selected position of adjustment, and cam means on said arms moving said trunn ion plate against the pressure of said spring in response to the pivoting of said arms from one pivotal position to another.

5. A drill steel centralizer, comprising a body portion having a projecting stub shaft, a plate slidable on said shaft, trunnions on said plate 4 angularly disposed with respect to each other and to said shaft, centralizer arms pivotally mounted on said trunnions, stationary angled jaws serving to guide said arms, spring means acting on said plate to press said arms into said jaws, and reaction surfaces on said jaws against which said arms bear in pivoting on said trunnions.

6. A drill *steelv centralizer for a rock drill adapted to advance longitudinally during operation, comprising a body portion having a projecting stub shaft disposed in substantial parallelism with said drill, trunnions supported by said body portion and axially located in a plane spaced from, but substantially parallel to, the longitudinal axis of said drill, centralizer arms pivotally mounted on said trunnions, a reaction plate surrounding said stub shaft and against which said arms bear in pivoting on said trunnions, said reaction plate and said arms being capable of re1- ative sliding movement determined by said stub shaft, complementary angled surfaces on said arms and said reaction plate brought selectively into cooperative relation by pivotal movement of said arms, and a spring surrounding said stub shaft exteriorly of the reaction plate and effecting a yielding engagement between said arms and said reaction plate.

7. A drill steel centralizerv for a rock drill adapted to advance longitudinally during operation, comprising a body portion having a projecti-ngl stub shaft disposed subs'tantlala4 parallelism with said drill, a trunnion plate on Usa-id -stlib 'f'.shaft, centralizer arms fpivotally-mountediorr said "trunnion plate, fa rea'ctionplate 'onfsa'idstub -f'shaft Ydisposedfadjac'ent'to thev trunnion 'plate'- and Kagainst-which said arms 'bear in pivotingfronv'said trunnion-- plate,y one 4of said-'plates being-slidable flcn'lgsaids'haftrelative to the other,` and jaispring l-surrounding said shaft -exteriorly v'of'bothfof'lsaid 'i plates VAand Y pressing upon said movable plate to resist sliding movement-'thereof andA toimaintain A `-safid:arms Land `v'said y reaction plate in 'yielding #engagement j A 814i dr'ill steel jcentralizer `Yfor -a ro'cldri-ll *adapted t, advance long'itudinally nuringpperation,'-compr`sing afbcdy'portiont'having aproje'cting stub shaft disposed in substantial parallelism with said drill, a trunnion plate on said stub shaft having two spaced trunnions fixed thereon, the trunnions on said plate being angularly disposed with respect to each other and t'o said shaft but axially disposed in a common plane substantially parallel to the longitudinal axis of said drill, centralizer arms pivotally mounted on said trunnion plate, a guide plate on said shaft and having angled jaws to receive said arms, one of said plates being slidable along said shaft relative to the other, complementary angular surfaces on said arms and said guide plate brought selectively into cooperative relation by pivotal movement of said arms, and spring means acting on'said movable plate to engage said arms in said jaws and to maintain said arms yieldingly in a selected position of adjustment.

9. A drill steel centralizer, comprising a, body portion having a projecting stub shaft, a guide plate slidably mounted on said shaft', a trunnion l plate slidably mounted on said shaft, centralizer arms pivotally mounted on said trunnion plate, grooved portions in said guideplate to receive said arms, means including a spring pressing saidv plates together to maintain said arms` in said grooved portions, reaction surfaces on said guide plate against which said arms bear in pivoting on said trunnion plate, and a plurality of angular surfaces on said arms brought selectively into cooperative relation with said reaction surfaces by pivotal movement of said arms and held in yielding contact with said surfaces by said spring.

10. A drill steel centralizer for a rock drill adapted to advance longitudinally during operation, comprising a body portion having a projecting stub shaft disposed in substantial parallelism with said drill, a guide plate slidably mounted on said shaft, a trunnion plate slidably mounted on said shaft exteriorly of said guide plate, centralizer arms pivotally mounted on said trunnion plate, reaction surfaces on said guide plate against which said arms bear in pivoting on said trunnion plate, cam means effecting a separating movement of said plates in response to pivotal movement of said arms, and spring means exteriorly of said guide and trunnion plates for returning said elements as said arms are moved into a selected position of adjustment,

11. A drill steel centralizer, comprising a body portion having a projecting stub shaft, adjustable centralizer arms supported by said body portion, a centralizer arm control plate slidably mounted on said stub shaft and movable thereon in response to adjustment of said arms, a reservoir in said body portion containing lubricating oil, and ports leading from said reservoir to the exterior of said shaft at points within the bearingsurace denedby the movement Qf Said conftrol plate. Y i Y. v A

12.* A drill steelcetreuzfr, eompisingebqy iportion having a `prm'ecting stub shaft, a trunnion plate slidably` mounted `on said Y stub shaft,

- centralizar arms pivotally mounted on said trunnion plate, means eiectinga sliding movement of said trunnion plate along saidshaftinresponse to `pivotal movement of said arms, a reservoir in said body portion containing lubricatingvoil, ports leading from said reservoir to the exterior of said shaft at points Within thev bearing surface deiined by the movement of saidtrunnion plate,and

Y ports 4in said trunnion plate leading fromthe inner periphery-thereof. to the exterior of the trunnions thereon andarranged to coincide with the *ports in said stub shaft at one point of the travel of said plate.

13. In a rock drill assembly comprising adrill,

` a shell mount therefor, and. a-feed screw oper-

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