US2085280A - Valve seat grinder - Google Patents

Description

June 29, 1937. M D, TYLER 2,085,280

' VALVE SEAT mammaA Filed Nov. 1, 19254 5y MM' "W 7%@ described in which the grinding member may beY .quickly renewed.

Patented June 29, 1937 UNITED s'rAT1a1sl PATENT OFFICEv aoazso- VALVE SEAT GRINDER Merle D. Tyler, Chicago, Ill. Application November 1, 1934, Serial No. 750,963

-3 Claims.' (Cl. 5.1-185) 'I'he present invention relates to valve seat grinders and is particularly concerned with grinders of the type adapted to be used in grinding extremely hard valve seats of internal combustion engines, such as. for example, the high speed tungsten or stellite steel valve seat inserts now being used.

One of the objects of the invention is the provision of an improved valve seat grinding tool which may be manufactured at a very low cost and which is adapted to be utilized in grinding very hard valve seats. A

Another object of the invention is the provision of an improved grinder which is simple in construction and requires a minimum amount of machine work in its manufacture.

Another object of the invention is the provision of an improved valve seat grinder which is sturdy and serviceable, accurate, and which may be manufactured at such a low cost that it may ,be purchased by a vast number of users who otherwise could not aord to purchase tools of this type. v

Another object of the invention is the provision of an improved valve 'grinder of the class described which is adapted to-bev used in relatively inaccessible places, such as on the valve seat located under an overhanging dash.

Another object of the invention ls the provision of an improved valve seat grinder of the class Another object of the invention is the pro vision of an improved valveseat grinder of the will be apparent from the following description and from the accompanying drawing, in which similar characters of reference indicate similar parts throughout the several views.

Referring to the single sheet of drawings accompanying this specification, Fig. l is a side elevational view of a valve seat grinder constructed accordinglto the present invention. shown in connection with an internal sizes.

combustion engine block, the block being in section;

Fig. 2 is a top plan view of thevalve seat grinder;

Fig. 3 is a sectional view taken on the plane of the line 3 3 of Fig. 2, looking in the direction of the arrows, with parts of the, driving shaft in section and other parts in elevation;

Fig. 4 is a bottom plan view of the valve seat grinder, with the pilot in section, on the plane of the line 4 4 lof Fig. 3, looking in the direction of the arrows;

Fig. l5 is an exploded view ofthe parts of the grinder, showing a fragment of the pilot and a fragment of the drive shaft;

Fig. 6 is a plan view of the abrasive covering sheet.

Referring to the drawing, I0 indicates in its ventirety the complete grinding equipment, which preferably consists of a motor such as a drill motor II having a chuck I2, a drive shaft I3, the grinder I4, and a pilot I5.

The equipment is shown in connection with an internal combustion engine block I6, which is provided with a relatively hard valve seat insert I1, and the usual valve stem guidel8. A number of different pilots I5 are provided, the sizes being suitable so that the pilots, which are accurately finished to cylindrical shape, may be rotatably mounted in the valve stem guides I8 of various types of engines which have guides of different The valve stem pilots I5 fit the guides I8 closely enough to center accurately the grinder I4 with respect to the seat I I and with respect to theaxs of the valve stem guide I8.

Allvof the. pilots are preferably provided with a reduced threaded portion I9 of the same size and preferably having right hand threads so that the tendency is for the pilot I5 to be threaded home into the body of the grinder I4 when the shaft is rotated in a right hand direction.

An annular shoulder 20 is located between the reduced threaded portion I9 and the cylindrical body of the pilot I5, and is adapted to engage a clamping member or spider 2|, which is utilized for securing the flexible abrasive element' 22 on the body 23 of grinder I4.

The drive shaft 3 is preferably, but not necessarily, provided with a flexibleshaft portion 24 located between two shaft sections 25 and 26 so that the grinder may be used in relatively inaccessible places by disposing the drive shaft of the motor I I at an angle, as shown in Fig. l, under the over-hanging dash 21. I

The flexible shaft portion 20 may consist of close 'together' and secured to the reduced ends 28, 23 lof the'shafts 25, 26 respectively.; This coil spring may be secured to the reduced ends 28, 29.111 anyof a number-of different wayssuch as, for example, by providing the reduced portions 28, 29 with relatively rough threaded formations of such shape that the coil spring-24 may be threaded over the spring, being threaded Ahome against'the annular shoulders 30, 3l.

The size of the cylindrical `parts of the shafts 25'and 26 and the size of the reducedportions 28 and 29 lare such that when the spring 24 is pilot I5 below.

located on the reduced portions 28, 29 thel outer surface of the springis flush with the cylindrical surfaces of the shafts 25, 26. The springs may also be secured in place in some embodiments of the invention by making the reduced portions 28, 29 slightlylarger than the space inside the spring 24 and forcing the springs on the reduced cylindrical portions 28, 29 where they are 'securedby' the frictional grip of the springs against the ends of the shafts. For this purpose the reduced portions 28, 29 may be slightly tapered, if desired.

Springs secured in either of the modes just described may be further permanently secured by welding, soldering, or otherwise. forming a relatively integral bond between the parts of the flexible shaft 24V and the shafts 25, 26. The lower end of drive shaft 26 is also provided with a reduced threaded portion 32 and with an annular shoulder 33 for use in seeming the shaft to the body 23 of the grinder I4.

The threaded portions I9 and 3 2 are prefer` ably of the same size so that the aperture or bore 34 in the grinder body 23 may be of the same size throughout and provided with threads of the same characteristics for fitting both the end of the shaft 26 and the end of the pilot I5. Thus thebody 23 may be threaded at one time for attachment ofthe shaft 26 above and the The grinder body 23 is preferably formed of die cast metal in a casting operation, and is provided with a plurality of frusta- conical surfaces 35, 36, 31, 38, separated by slots 439. -These sections of frusto-conical surfaces 3538 all form parts of the same frusta-conical surface and correspond in angularity to the angularity of the valve seat upon which the grinder is to be used, such as, for example, forty-five degree valve seats, sixty degree valve seats, or thirty degree valve seats. Obviously, grinders of any angularity may be made, and those just listed are merely exemplary of the most common shapes. l

At its lower end the grinder body 23 is provided with a iiatsurface 80, which is adapted to engage the inner fiat side of the clamping member or spider 2l At its upper end the valve seat body 23 is preferably provided with aflat upper surface 4I which may be engaged -by tool holders in some types of driving equipment, 81nd on other occasions it may be engaged by the driving end of an ordinary valve seat lapping ma'- chine. di is provided with the pairs of holes 42, d3 which perform the'same function as the slot or holes in the upper end of the valve stem for receiving the projecting ends of the plate onv the end of a geared valve seat grinder of the type which rotates-the valve or grinder forward and backward.

Body 23 of the grinder is preferably longer or deeper in a vertical direction than the dimen- For this purpose the upper fiat surface r 2,085,280 a fairly heavy helical spring havingits-coils sion necessitated for the frusta-conical surfaces a cylindrical outer surface 44. Since a considerable portion of the body is removed in forming the slots 39, it is also desirable to providethe lbody 23 with a cylindrical boss 45 at its upper end, thereby giving the body greater strength and providing more material for joining the frust-conical parts 35-'38 together.

The 'clamping member or spider 2l preferably consists of a spring steel member which may be made of non-corrodible material, such as stainless steel, Aorirom ordinary spring steel. It is preferably provided with a centrally located aperture 46 for passing the reduced threaded end I9 of the pilot I 5, and with an annular body 41.

Projecting radially `from the annular body 41 are a plurality of integral-strips or spring fingers 88 which have been bent upward from the annular body 41 at the points 49 in such manner as to engage the flexible ab'rasive covering 50 and draw it taut on the Afrusto-conical surfaces As observed in Fig. 3, the angularity ofthe spring fingers 48 is such that any excess of exiicient firmness so that there is nopossibility of its becoming -loose under operation. However, the proportions of `theannular abrasive covering 50 and the grinder body 23 are such that the abrasive becomes tight slightly before the clamping member 2| meets the Vlower end 40 ofthe body 23, and the spring ngers 48 are slightlyv iiexed and placed under tension when the clamping member 2i is driven home'against the end 48 by the annular shoulder 20 of pilotl I5.

The abrasive covering I5 may consist of any form of flexible abrasive having a paper or fabric base, the latter being preferred on account of its greater flexibility and greater tensile strength. Therefore, the abrasive covering 58 preferably consists of .emery orcarborundum v35i-38, and is therefore generally provided with 25. yible abrasive over that required to cover the v cloth in the form of an annulus, as shown in Fig. 6..

It should be observed that the aperture 5I in the annulus 50 is larger inthe blank pattern than it appears in plan, when the slack has been taken up, and the abrasive is secured to the body 23 as shown in bottom plan in Fig. 4.

It will thus be observed. that I have inventedA be provided with a exible upper shaft at a minij mum expense. by means of the structure described, and the machining operations involved are reduced to a minimum, since the body of the grinder may be cast, and it is only necessary to thread the aperture in the body.

While I have illustrated and described a preferred embodiment of my invention, many modiflcations may be made-without departing from the spirit ofthe invention, and I do not wish to be limited to the precise details described, but desire to avail myself of all changes within the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a tool for grinding valve seats, the combination of a supporting body having a substantially frusto-conical backing surface, said body being formed with a plurality of radially and inwardly extending slots, each of said slots extending substantially in the direction of an element of said frusto-conical surface located at said slot, a flat annulus of flexible abrasive material carried by said body in engagement with said l5 backing surface, said annulus having its slack taken up by extending into said slots, and a relatively stii yet resilient metal member centered on said body outside said annulus and having a plurality of legs, each of said legs extending 20 into one of said slots, and forcing said slack 'abrasive into said slots, said legs holding said annulus taut against said frusto-conical surface by virtue of the resiliency of said legs, which are adapted to be flexed to maintain a predetermined 2 5 tension on said abrasive, said body having a threaded bore, a pilot member having a reduced threaded section adapted to be threaded home in said bore, said metal member having an aperture receiving said reduced threaded section, and

30 said pilot having a shoulder engaging said metal member to clamp saidmetal member against said body when said legs are placed under tension.

2. In a tool for grinding valve seats, the com- 35 bination of a metal body provided with a plurality of substantially frusto-conical surfaces formed with the same generatrix and spaced from each other by a plurality of radially inwardly extending slots, said body having a sub- 40 stantially iiat upper surfacey and being provided with a centrally located threaded bore on its frusto-conical side, a flexible abrasive annulus of suflicient size so that when it is placed upon the frusto-conical surfaces of said body and sub- 45 stantially conformed thereto said frusto-conical surfaces will be substantially covered and the slack of said annulus extends into the slots, the depth of said slots being sumcient with respect to the amount of slack in said annulus so that '50 the base ofthe slots will notl prevent the abrasive 55 one arm extending into each of said slots, and

said arms extending diagonally from the body of said spider in substantially the direction of the base of said slots, said arms being bent at an angle whereby they are adapted to engage the abrasive annulus and take up all of the slack therein and draw the annulus taut on the frustoconical body when the spider is driven into said slots, and a pilot having a threaded end and a shoulder for engaging said spider, said threaded end being located in said threaded bore whereby sad pilot is adapted to exert the tensioning force by driving said spider in an axial direction toward said body.

3. In a tool for grinding valve seats. the conibination of a metal body provided with a plurality of substantially frusto-conical surfaces formed with the same generatrix and spaced from each other by a plurality of radially inwardly extending, slots, said body having a substantially flat upper surface and being provided with a centrally located threaded bore on its frusto-conical side, a flexible abrasive annulus of sutlicient size so that when it is placed upon the frusta-conical surfaces of said body and substantially conformed thereto said frusto-conical surfaces will be substantially covered and the slack of said annulus extend into the slots, the depth of said slots being sucient with respect to the amount of slack in said annulus so that the base of the slots will not prevent the abrasive from being drawn taut on said frusto-conical body, a metal spider having a centrally located aperture for registry with said threaded bore, and having a plurality of radially extending arms, one arm extending into each of saidV slots, and said arms extending diagonally from the body of` said spider in substantially the direction of, the base of said slots, said arms being bent at an angle whereby they are adapted to engage the abrasive annulus and take up all of the slack therein and draw the annulus taut on the frusto-conical body when the spider is driven into said slots, and a pilot having a threaded end and a shoulder for engaging said' spider, said threaded end being located in said threaded bore whereby said pilot is adapted to exert the tensioning force by driving said spider in an axial direction toward said body, said threaded bore extending through said body, anda drive shaft comprising a threaded metal rod driven home in the upper end of said bore, said rod having a spirally wound exible section secured thereto and a second drive rod for grip by a chuck carried by the other end of said spiral iiexible section.

MERLE D. TYLER.

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