US2363384A - Method of grinding valve seats and similar areas - Google Patents

Description

Nov. 21, 1944. R.- s. BEVERLIN METHOD OF GRINDING VALVE SEATS AND SIMILAR AREAS Filed April 17, 1944 IIIII I 1 rill/1 i v Furthermore, in

1 Patented Nov. I

. 'I ivrn'rnooomonmnme VALVEQSEATSIAND, a 1 sIMILAR R As corporation .ofaOhio .Appii 'iaitnat f 7 wersefiam- 531,391

flsolaims. (c1. 51+241- v are eylinderfwith a part in iullandwitha valve seat grinding tool in operative position "therein,

i jl'l'his invention relates "primarily to the artjfof indihg valve seats, offinterna'l cornbustion'engines; particularly those of the. type having closed Qcylinderheads withthe .valve seats in such heads,

jasiri radialai'rc'raft engines," thus requiring access thereto. forij'giindin purposes to be had through the open'inner end of the cylinder.

' ,In'thegrindi "g of valve seats in such a cylin- ,dei the: grinding tool .is} disposed within the -"closed"cylinder head end thereof where iteis. difficult ofaccess for the purpos'e'of applying thereto the necessary; grinding pressure, and theoylinder together with means attachedthereto fon'pracbore is usua'lly of suchjsmall diameter that the is vless than that normally required, the efficiency of a the grinding: operation is gradually. reduced,

'both in time and results, and this isincreased if the plane of the 'valve' seatis inclined to the cylinder axis, 1 t I v the grindingsof such Ivalve seats, 'a' liquid coolant is introduced interiorly of t j'tool ,must'besmall sothatitsWei'ght is notsuifl- ;cient to ,impart'. the desired grinding pressurej "agains t .thevalveseat. 'If'the grinding pressurethecylinder' and flows down to and in engage- I ment Withthe edge of the grindingwheel. The

"hi h 'spe'ed'ofthe wheel causes this-coolant to flow to and be thrownfrom the peripheral edge ;of the wheel by lcentrifugalqaction so that very "little if any of the coolant will reach the grinding surface, thereby resulting 'in a hot grinding operation. An object of theinvention is the provision of a simple, eflicient and 'novelfrnetho'd andmeans for acting on the grindingwheel of a valve seat grinding .tool through the valve seat passage to apply a predetermined grinding pressure thereto Another'object of the" invention isf to'utilize pneumatic suction through the valveseat passage ofaninternal combustion engine cylinder to act on a grinding tool for thefvalve seat. of such passage to hold it to the seat'withafpredeterrnined pressure to effect the desired grinding operation. Another object of the invention is the provision of'aisirnple' jand efiicient method, ofpneumatic -character, operable throughthe valveseatopening of a cylinder of theclas's describedto not (only act to h a inding wheel in seat grinding "ticing the feature of the'invention."

Referring to the drawing, 1 designates a cylinder'of afradial typeaircraft engine, with the head or closed end thereof I provided-with two passages 2 one of which forms the inlet passage andthe other the exhaust passage forthe cylinder vand each havingat its inner end thecus tomary-valve seat 3. In eachpassage 2,-in-axia1ly aligned relation to the valve seat opening his a valve stem guide "opening 3 4 adaptedto receive and guide the 'movements "of the associated valve stern (not shown); when the 'valve'is" removed *from the cylinder head, the guide opening :4

receives and centers a pilot stem 5, onefend'ot which -pro5ects through the -valve 'seat'iopening and into-the cylinder '-to'-form a mount and guide for a valve'seat grinding tool 6, as well understood in the art. Thetool 6 is preferably-but not construction -due to *itsuse in cylinders having small diameter bores. Nothing novel is claimed for the-tool itself and -ittherefore need not be I --more specificall 'describedp :A' liquid coolant; 'in thepresent instance, is

suppliedto the surface-being ground from a hose "or tube-8 which receives its supply of coolant from any suitable source and-has its discharge end terminating within the cylinder adjacent to one side so'thatthe coolant will flow down-the inner side wall of the cylinder to the valve seat a3 being'ground; I

position under a'predetermined pressure, but also to prevent a coolant supplied to thewheel' from being drawn away fromits seat grinding surface by centrifugal action. v I

Other objects and advantages of the invention will be apparent from the following description and from the accompanying drawing. i 1

The drawing is a central longitudinal section During the grinding-of a valveseat thesmallnessand c onsequent lightness of the tool 6 prevents =it-from exerting by g-ravity action-the necessary pressure of its grinding wheel; -|flagains't the-' valveseat 3 to eifect a -rapid and -efficient grinding operation, and due to'the small diameter of the cylinder bore it"is, difiicult to apply any manual pressureto the tool for the purpose. In

" order to compensate for this lack of grinding pressure, the outer end of the passage'2 leading to or from the valve seat opening, as'the case may be, is connected up to a .vacuumfsource whereby a suction action is applied through such passage and acts against the grinding wheel I to hold it to the valve seat under a predetermined pressure, which is determined by the suction pressure. This method of applying grinding pressure to the grinding wheel is not only eflicient in obtaining the desired grinding action of the wheel on the valve seat, but also in drawing the coolant to the valve seat and coacting grinding surface of the wheel to have the desired cooling action thereon rather than being carried to the extreme peripheral surface of the wheel away.from the valve seat and thrown therefrom by centrifugal action. This initself is an important feature.

In the illustrated embodiment of the invention, l designates a tank for a liquid coolant and into which the open end of a suction pipe is submerged. This pipe connects with a suitable suction source indicated diagrammatically at l2, and between this source and'the tank [0 the pipe has a side connection at I3 with the outer end of the passage 2, the valve seat of which is to be ground, The connection I3 is adapted to seat against the outer marginal edge wall of the passage 2 and to be secured thereto by screws, or in any other suitable manner. a The vacuum pressure may be determined by the height of the coolant column in the lower end of the pipe I and in practice it is found that from sixteen to twenty inches raise of liquid in the pipe is sufiicient. The top of such column, however, should be below the connection l3, so that the coolant which enters the passage 2 may flow outward therefrom through the connection I3 and pipe, I I to the tank [0. In the present instance, the coolant supply tube 8 leads from the tank I0 and has a pump l5 interposed therein. 7

While, in the use of an eccentric type of grinding tool, as illustrated, a clearance space is present between the seat and grinding wheel due to the eccentric seatingaction, this clearance is customarily about twenty-one thousandths of an inch at its widest point and therefore is not sufficient to seriously interfere with the desired suction action on the wheel. The presence of such clearance also facilitates the drainage movement of the coolant over and through the seat by the suction action. i v

While the invention has been particularly described for' use in connection with the grinding of valve seats disposed interiorly of engine cylinders, it is not desired to restrict it to such use, as it may be used to advantage in the grinding of any area which is circular or substantially circular and has a passage leading inwardly therefrom, whereby suction within the passage at the inner side of the grinding tool will permit atmospheric pressure, acting on the tool at its outer side, to hold it to the seat or area being ground.

I wish it understood that my invention is not limited to any specific construction, arrangement or form of the parts, as it is capable of numerous modifications and changes without departing from the spirit of the claims.

Having thus described'my invention, What I claim as new and desire to secure by United States Letters Patent, is:

1..The method of holding a valve seat facing passage.

tool in operative coaction with a valve seat at the cylinder end of a passage having communication with a cylinder, which consists in creating a vacuum within the passage whereby atmospheri pressure at the cylinder Side of the tool acts on the tool to hold it under predetermined pressure in facing coaction with the valve seat.

2. The method of holding the grinding wheel of a valve seat facing tool in predetermined grinding coaction with a valve seat at the cylinder end of a passage which is in communication with the cylinderof an internal combustion engine and wherein the wheel closes or' substantially closes the passage, which consists in ap-' plying a predetermined pneumatic force on the wheel through said passage to hold it in predetermined grinding coaction with said seat.

3. In the art of grinding the valve seats of the cylinders of internal combustion engines wherein the rotatable grinding Wheel of a valve seat facing tool has grinding engagement with a valve seat internally of the cylinder and wherein a liquid coolant is supplied to the wheel, the method of preventing such liquid from being thrown away from the seat grinding portion of the wheel by centrifugal action, which consists in causing a pneumatic force to act through the cylinder and around the grinding wheel to counteract the said centrifugal force and cause the coolant to partially at least flow outwardly from the cylinder over the valve seat.

4. In the art of grinding the valve seats of cylinders of internal combustion engines wherein the rotatable grinding wheel of a valve seat facing tool has grindingengagement with a valve seat internally of the cylinder and wherein a coolant is supplied to the wheel and seat, the method of holding the wheel to the seat. with predetermined grinding force and also preventing the coolant from being thrown from the seat by centrifugal action due to the rotation of the wheel during grinding, which consists in applying a predetermined suction on the wheel away from the cylinder and through the passage leading from within the valve seat.

5. The method of holding a grinding tool to an area to be ground and wherein aspace is provided within such area and is open thereto, which consists in creating a vacuum Within said space-whereby atmospheric pressure at the outer side of the tool with respect to said space acts on the tool to hold it; under predetermined pressure in facing coaction with said area.

6. The art of grinding substantially circular areas bounding an open passage leading inwardly through said area wherein a rotatable grinding tool has grinding coaction with the area in substantially closing relation to said passage and wherein a coolant is supplied to the wheel and area, the method of holding the wheel to said area with predetermined grinding force and also preventing the coolant from being thrown from the area by centrifugal action due to the rotation of the wheel during grinding, which consists in applying a predetermined suction in said passage" and to the side of the wheel exposed tothe ,RQBERT s. ,BEVERLIN;

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