US1860628A - Pneumatic tool - Google Patents

Description

May 31, 1932. 'l F. nh. SLATER PNEUMATIC TOOL Filed Dec` 3, 1931 Patented kMayY 31;!'1932y i FRED? v rNY, or JERSEY CITY, NEW JERSEY, CORPORATION OF nawarmsnr rNEUMATrc .'rooL` applicati@ and December 3,1931, seria; No. 578,665,

This invention relates to pneumatic: tools, but :more particularly to a valve mechanism for tools Oflthis character.

Y` One object of vhegimvention is to retain the distributing valve iirrnly seated. in its limiting `positions irrespective of theaction ef'the piston which it controls.I

@Other Objects-Willibe in ipart Vobvious and y in jp'artffpinted out hereinafter# f :In the accompanyi lg drawings illustrating H `L n Y ther invention and in which lsimilar reference characters refer to similar parts, f A 'Figure iis-ia longitudinal elevationin sec g tion Of' a portion of a rock drillequipped with y., valve mechanism constructed in Vaccordance with the Apractice of theinventionand Figure 2 isa. transverse view taken throufh reetifon indicated by the arrows.

Y' r-Referring moreparticnlarly tethe drawV Yings, Adesignatesin general, a rock.y drill eemprising a cylinder l B having f a ypieten vchamber C te accommodate a reciproeatery hammer pi'stengl). The piston D yis ofthe differential typehavinga head "Fi and a stem G at the front end of the head extending: slidablythrough the rvfrontend' of the cyl-v inder' B for delivering blows against a Workingimplement, such as a 'drill' steel (not shown); I In-@the cylinder Bris a free exhaust H Vwhichy controlled bythe head F of K L the; plate Xand the cylinder BtQtheLron-t end' ofthepistonVV chamber Offer admitting the "piston El;

yWliich extendsa rielbar L tofinterlockingly cngagetherpiston D in a Well known manner fer imparting rotarygfnievement thereto. At therear end of' the. rifle bar Lirs'a head O which seats iiponfthefbackcylinder Washer J and carries rpawlis P fori engagement with teeth Qo a ratchet; ring encircleskk the head OJ@ Y Y f v The ratchet ring vE and the headQin: the

Y present.insta-nce;` are arranged 'within a'hore yerreeess'Sini/che `front end of' a back Twhich risse-ated on the'back cylinderwasher y, Jfand which may be. secured A te theeylinder "B in any suitable'manner;V

distribution ef-pressiire flnid 'tothe ends of the piston chaniber C foi-'actuating the Piston D S efeted `by valve mechanism Ul arranged, in the present instance, onthe side of thecylinder Band comprising a valve chestz V which preferably includes a y pair of plates W and); bolted, or otherwisesecillator'y iilate' distributing :valve ZV which fis held against vlongitudinal lmovement in the,

valve chamber Yfby a pin biseatedinthe Y plate 'W and extending into an aperture c in the lvalve The Oppositely extending Wings Zand e of the valve are tapered ,from

the' tran'sYersefmedianline' ofthe valve te-Y i wards' the enter edges,thereof in 'the usual manner and are kadapted to'seatupon seating surfaces f endg,` respectively,- en the plateX.

Leading frmnthe seating surface f tothe rear end of A'the piston chamber Grandezztending threnghfthepl'ateX and the cylinder B5 Vis agrearfinlet passage h Lthrough which pressure Afluid flows into the rear end'ofthe piston chamber crfdiving tliezpiston D'forg Wardly on itsv rWorking stroke, andsaid inlet; passage'is'controlledabythe wingelei the valve;

Similarly, yfrom the v:seating surface. fleads al front inletfpassagej which is controlled by' i the wing 'fl of the valve andv extends through pressure fluid theretobtoy drive thel piston reairwvardlyrr intoabore ein the plate W. A passage pin the :pla-te W conveys. suchpressure fluidv inta the valve charnherl Y- and yis edntrl'led faf T he rock drill so position illustrated in'Fignre 1,v wherein the WingV e' of the valve: Yis raised andtfhepistorr lDflies. rearwardly-ofthe exhaust porty Hf ,pressurel luid clvvs Over'the raised end of the l wing e through thefifnlet passage ih into the far deSCribedfinayfbe-e y a known type Of whichv the -operation;` is Fas fallo-.Ws lith thedistribntinggvalvebZ in the? meterla, or EASTON, rENNsYLvANm, Assi'GNOR iro manson-RAND ycoin-...Q

y C1 waraiy. 'rov this rear end of the piston rchamber C to drive the piston D forwardly on its working stroke.

t After the piston D covers the exhaust port H the air in the front end of the piston cham- 5 ber C'will be compressed and will act against the seated wing d of the valve. Y

When the compression in the 'front end of the piston chamber reaches a value together with the force of the suction created by the lo pressuref fluid flowing over the wing e eX- ceeds the pressure acting on the upper surface Y of the seated wing d, the valve Z will be rocked to its othery limiting position.

the piston chamber will then be cut offl and pressure fluid willfflow over the raised end of the vwing e and act against the front end of the'valve F ofthe piston D to'drive said piston rearwardly. 1

f Normally,in theabsenceof anyforce tending to retard the free movement of the piston D, the piston may reciprocate at a rapid rate and the action thereof, together with that'of Y ythe distributing valve Z, will be substantially as as'hereinbefore described.' kIn other kwords, the piston D'will travel its full nominal stroke and will deliver a yheavy blowk against the working implement during each cycle ofL movement of the pistonl andV of the valve Z. Thereare instances during the operation of tools of this character when, due to irregularities in the rock being drilled, the working im- Dlement-becomes stuck or bound in thedrill hole to such an extent as to interfere seriously withthe rotary movementA thereof, such as may be induced by the rotation mechanism including the rifle bar L, its pawls P and the ratchet ring` f Such retardation of the rotation mechanism, in consequence, effects the movement of the piston'D.

f r'Whenever vthe working implement offers great resistance to the action of therotation mechanism the piston D reciprocates at a reduced rate ofspeed and, as a result,any pressure fluid which leaks from the valve chamber'Y beneathfthe seated end ofthe valve and into an yend of the piston chamber ,will therefore build up suflicient'pressure in that end yofv the piston chamber to raise the'seated end of the valve. `The piston vD will then `be reversed without completingits stroke. In Y other words, the valve may be tilted before the piston head F has uncovered the exhaust port H; f This is objectionable for the reason that the full force of which the piston D is capable .will then notfbe applied to the working implement to wrest it freefrom `the rock surface.y "i

f In view of thel foregoing facts it is contemplated 'to provide means intended to assure the retention` of the valve Z in its limiting position throughout all periods of operation ofthe tool until the piston D has completed its nominalstroke,both forwardly and rear- They supply of pressure fluid to-the rear end of f end thevalve chest, and

A whichis located rearwardly of thetransverse rmedian `line of the relief valve chamber 1',

75 opens into a recess 1J 1n the seating surface g.

Leading from the relief valve chamber r, at a point intermediate its ends, is a relief passage w which extends through the plate X andthe cylinder B and opens to the atmosphere. Y

'Disposed in the relief valve chamber 1' is a relief valve a: which comprises-a pair of end heads jz/ anda connected` by a reduced stem 2. The front and rear endsof the valve 'constitute actuating areas-3 and 4, respectively, against which .pressure -fluid acts to throw the valve'lfrom ,one limiting position to the other. y'Such pressure fluid is conveyed to theV frontend of the valve. chamber 1 by a passage 5 vwhich communicates with the inlet passage I7',iand pressure fluid is `conveyed into vthe'rear-end of the valve chamber 1' from the inlet 'passage h by a passage 6. Y i

The vmanner `in which'the relief valve a1 operates is as follows: Upon; the admission of pressure fluid into the ends of the piston chamber, as for instance, when admitting pressure fluid tothe rear end of -the piston chamber, a portion of the pressure fluid flowing. k'through .the inletl passage yL ypasses through they passage 6 into the rear end of the valve Lchamber 1' and acts. against the actuating surface-4 to` move the valve ai. forwardly In this position of the valve :v the recess u will be in communication with the atmos# phere through fthe port s, the intermediate portion ofthe valve 1' and the relief passage/w.' Any pressure fluid thenvleaking beneath the seated wing d of the valve will cscapeto the atmospherethrough these channels and only the compression fromthefront end of the piston chamber Cvflowing through LUG the inlet passage j willact against a comthe piston has reached a position during its 12tforward travel where it will uncover the exhaust port 5 When the piston reaches this portion there will be a direct flow of pressure fluid from the valve chamber' through the piston lchamber and the exhaust port H and the suction of the pressure fluid flowing over thewing e, together with thecompression acting against the wingy d, will then tip the valve.

In the new position of ythe valvepressure fluid ilows into the front end of the piston chamber C. i-iportion of such pressure fluid will flow through the passage into the front f end of r.the valve chamber?" and actagainst the actuating surface 3 to move the valve ,m

v rearwardly. n ln this position of the valve m passageH, whereupon the valve Zwill again Y be shifted. l

distributing valve chamber, inlet passages leading from the distributing valve chamber tothe cylinder, an oscillatory plate valve in 'the distributing valve chamber to control the inlet passages, seating surfaces for the valvel having recesses therein, ports connecting the recesses with therelief valve chamber, a relief-.passage leading fromthe relief Avalve chamber to the atmosphere, a valve in the relief valve chamber to control communication between the ports andthe relief passage, and passages for conveyingy pressureV fluid from the inlet passages into the relief `valve chamber to actuate the relief valve.

Intestimony .whereof I have signed this specicatioi'i.l

FRED M. SLATER.

As will be apparent from'the foregoingk v description, only comparatively small lareas Y Vof the seated ends ,of the valve will be exposed to such pressure iiuid as may leak beneath the valve and, ofcourse, also to compression acting through ther inlet passages associated with the several ends of the valve chamber Y. It will further be apparent that the valve m will be shifted in timed relation with the valve Z to maintain a considerable portion of the seated posed to atmospheric pressure. The valve Z will,.in consequence, remain firmlyk seated in its liinitiiig'positions and will not be tilted until the piston D has reacheda position to uncover the exhaust port H, irrespective of Whether thefpiston D is reciprocating rapidly or at a slow rate of speed.

I claim: f

l. In a pneumatic tool', the combination of a cylinder and a piston thereinfa valve Achest having a valve chamber, seating surfaces in thevalve chamber and havingre-v cesses therein, ya distributing valve V1n the -valve ,chamber for distributing pressure fluid to the cylinder, passages for communicating y the recesses with the atmosphere, and a sec` ond valve movable in timed'relationv with the Vfirst saidvalvefor controlling the passage.

a cylinder and a piston, a valve chest having a distributing valve chamber and a relief valve chamber, seating surfaces in the dis` tributing Vvalve chamber havingV recesses therein, ports connecting ther recesses with the relief valve chamber, a relief passageV leading from the relief valve chamberto the atmosphere, a valve inthe relief valve chamber to control communication Ybetween the Vports and the reliefpassage, and passages for conveying pressure fluid into the relief valve chamber for actuating .the relief valve upon endsof the valve eX- 2. In apneuniatic tool, the combination of y the admission of pressure iuid to thecylinder.

- 3. lIn, a pneumatic tool,the combination of a cylinder and a piston therein, a valve chest e having a distributing valve chamber and a im l

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