US2135900A - Grinding tool - Google Patents

Description

Nov. 8, 1938. H. W.'KULP 2,135,900

GRINDING TOOL Filed March 19, 1935 3 wuemkm;

Patented Nov. 8, 1938 pro s'rA'rs ATET Fi i GRINDING TOOL Application March 19, 1935, Serial No. 11,859

Claims.

This invention relates to tools for grinding the valve seats of internal combustion engines and is primarily intended for use in grinding or lapping the conical faces of special hard steel or other material valve seats now frequently driven, frozen or otherwise inserted in the engine block. While this invention is particularly designed, suited and intended for grinding valve seats of internal combustion engines it may be used to grind or surface to which it may be found to be adapted and the following description and claims are to be read with this understanding.

With the advent of the automobile it at once became manifest that the valves and valve seats must be ground at frequent intervals to remove the carbon deposits so that the valves could seat properly and for many years thereafter the usual practice in accomplishing this was to remove the valve springs, apply a wet abrasive or what is known as grinding paste to the valve or seat or both and then to rub the valve against the seat with an oscillatory rotary motion until the opposing faces of the valve and seat had been properly ground. During such grinding operation the valve stem fitted in, and was held and centered by, the usual-valve stem guide or bushing. At first it was rather generally felt that such oscillatory motion was necessary in order to tumble the individual crystals of the grit around thus preventing their becoming embedded in the valve or seat and from making minute scores in the valve or seat or both. Of late years this viewhas been in large part or entirely discarded by many engineers and mechanics in the art on the ground that the cutting action of the individual crystals was modified by the cutting action of the mass of crystals.

During the last few years some engine manufacturers have inserted special hardened steel or other metal or material valve seats in the engine block around the exhaust ports and in some engines around the intake and exhaust ports and this practice is increasing. With such construction the conical or annular seating face of the 4.5 valve seat is made quite narrow and when by repeated grinding it has been unduly increased in breadth it may be entirely replaced by a new seat, it being recognized that the narrower the seat the less the risk of carbon lodging on it and in- 5Q terfering with the seating of the valve, and the harder the seat the less is the risk of its pitting and preventing the proper seating of the valve.

It has been found, however, that these hard seats present difliculties when it is necessary to grind the valves and seats and that because of lap any valve seat or any annular concave conical 7 such difficulties many small and medium size garage and repair or service shops which previously regularly ground valves and indeed devoted a large part of their time and services to such work have had to turn such work away as they were not equipped to handle it and could not stand the expense of the costly equipment heretofore necessary.

t was found that these inserted hard seats wer so hard that the old method of applying a coating of lapping or grinding paste and then rubbing the valve against the seat was too slow, re quiring so much time as to make the cost prohibitive. To meet this situation Various special reaming and abrasive cone grinding machines were developed and have been, and are being, used by a number of the larger and better equipped garages and service and repair shops, but they are very expensive as compared to the usual automobile mechanics tool, most of them rotate at a high rate of speed continuously in a single direction, so that notwithstanding the hardness of the seat unless great care is exercised the seat will be excessively reamed or ground down to such extent that its seating face will be too wide and the seat will have to be removed and replaced and these seats are expensive, aside from the time and work required in such removal and replacement. Where a grinding cone is employed, such as a cone of carborundum, emery or the like, a great deal or" heat is generated and fine particles of grit are brokenor scraped off in the form of a fine dust which floats through the air and settles over all exposed surfaces of the engine, that is, on the cylinder walls, pistons and other working parts of the engine with resultant serious damage to the engine. Attempts to remedy this last situation have been made by ar ranging a dust hood close to the grinding cone and sucking the air from this hood with a suction apparatus and while this has eliminated much of the dust it has given rise to another serious objection in that it has very materially increased the already exorbitant cost of the equipment.

The present invention has been developed with all of the above considerations in view and has for its primary objects, to provide a small simple tool eflicient for the purpose and which may be made to sell at the price of an ordinary garage tool and Within the means of the country crossroads garage or repair shop; to provide such a tool which may be used with an adapter and driven by hand or inserted in the chuck of a machine and be power driven; to provide such a tool in association with means for supplying,

and renewing the supply of, lapping or grinding paste compound to the operative portion of the conical grinding face whereby the tool will grind or lap wet, or by means of a wet or pasty abrasive agent, whether hand driven at a slow speed or motor driven at a high rate of speed of, for instance, 2,000 B. P. M., or whether driven constantly in one rotary direction, or given an oscillatory rotary movement, so that the chance of fine, hard, gritty particles in a dry state being scraped oif and floating through the air to. settle on the working parts of the engine will be entirely avoided; to provide such a tool with a lapping or grinding paste compound reservoir having discharge conduits or channels extending through, or adjacent to, its grinding face so as to feed the grinding compound to its point of use as required; to provide in association with said reservoir adjustable means for forcing said compound through said conduits or channels; to provide in association with said forcing means a cushioning or compressible element acting by its expansion, and independently of the adjustment of said forcing means, to expel said compound from said reservoir through said conduits or channels; to so form the reservoir, forcing means and cushioning means as to prevent the compound from squeezing up between the forcing means and reservoir to any material amount while at the same time avoiding the freezing or frictional binding together of the forcing means and the opposing face of the reservoir; to provide such a tool wherein the operative or conical grinding face may be, as worn or grooved or scored or otherwise defaced, repeatedly dressed or ground down or refaced or trued until practically ground away and until such time be used without impairment of efficiency of the tool in any way; to form the grinding portion as an easily separable element so that when finally it has reached the end of its usefulness it may be quickly removed and replaced by a new duplicate grinding portion; to so form the elements of the tool that the reservoir may be formed in any suitable and/or desired manner or method, as by die-casting, and the grinding portion, cone or element may be formed by any suitable method or in any desired and/or suitable manner, as by turning from bar stock, and the parts be quickly assembled and firmly and rigidly held in proper relation with the portions of the discharge conduits extending through the reservoir in proper registry with the portions of the conduits extending through the grinding portion or cone, or so that when assembled the discharge of the grinding paste compound from said reservoir will not be blocked or seriously impeded, all to the end that economy of manufacture may be promoted and the highest degree of efficiency maintained; and to provide a tool which may be motor driven at a high rate of speed, or may be driven by hand as by the use of a screw driver or suction cup device, and may be rotated continuously in a single direction, or given an oscillatory rotary direction, all as may be required or preferred in accordance with the other shop equipment available and/or the personal views or convictions of the particular mechanic or the person in charge.

In this application I show and describe only the present preferred form of my invention simply by way of illustration of the practice of my invention as required by the law. However I clearly appreciate that my said invention is capable of embodiment in a number of other and different forms and that the several details thereof are capable of modification in a variety of different forms, and, therefore, the drawing and specification herein are to be considered as merely illustrative and not as exclusive.

In the accompanying drawing:

Figure 1 represents a side elevation of a tool embodying my invention, with an adapter applied thereto;

Figure 2, a sectional view on the line 22 of Figure 3, looking in the direction of the arrows, the shaft being shown in elevation;

Figure 3, a bottom plan view; and

Figure 4, a cross-sectional view on the line l4 of Figure 2, looking in the direction of the arrows.

Referring now in detail to the drawing, I designates the tool shaft formed with two diameters, the end of the larger diameter forming an abrupt shoulder 2. The reduced or small diameter portion is formed with a short cylindrical portion interposed between the shoulder 2 and the externally screw-threaded portion 4. A rib, key or feather 8 preferably permanently secured to or in the shaft I, as'by welding, projects radially beyond the cylindrical face of this portion of the shaft I preferably substantially for the length of said portion between the shoulder 2 and screw-threaded portion 4. The upper part of the larger diameter portion is reduced as at 3 to fit into the socket of an adapter I8 or into the chuck, not shown, of an electric motor or other power driven unit, not shown. Immediately below said reduced portion 3 the shaft I is formed with an external screw-thread 'I.

The cup-shaped grinding or lapping paste compound reservoir or cup or shell I0 is formed with a central opening in its bottom of such diameter as to make a freely sliding snug fit with the cylindrical portion of the shaft I between the shoulder 2 and thread 4 and is notched out at I3 to receive, and be locked against relative rotary movement by, the rib, key or feather 8, and the similar cup-shaped cone grinding element or member 9 has its top wall formed with a similar size and shape similarly notched opening forthe same purpose. The cup or reservoir I 0 is slipped over the lower end of shaft I and shoved up against the shoulder 2 with its slot I3 receiving the key 8 and its cup-shape interior presented upward. cone 9 is similarly slipped over the lower end of shaft I with its top presented toward the bottom of cup I 0 and is similarly shoved up shaft I until its top surface is in engagement with the bottom face of cup I0 and its central opening is disposed about the portion of shaft I between shoulder 2 andscreW-thread 4, with its slot I3 receiving the key 8. Thereafter washer 5, which may be of iron, steel, or any other suitable material is slipped over shaft I and moved up against the lower face of the top of cone member 9, after which nut 6 is slipped over the lower end of shaft I and turned up tight on the threadedportion 4 to clamp the washer 5,cone member 9 and cup In tightly between the shoulder 2 and nut 6, holding them against relative axial movement and the key or rib 8 fitting in the slots 'I3 serving to lock them against relative movement in a rotary direction.

The extreme radially outer portion of the bottom of the reservoir or cup I0 and the annular wall of the grinding or cone member 9 are each formed preferably at diametrically opposite points with two very small bores IZ'preferably approximately of a diameter not exceeding the Thereafter the grinding member or diameter or cross-sectional size of the average domestic hand sewing needle or say of three sixty-fourths of an inch in diameter, said bores preferably extending substantially parallel to the axis of shaft I so as to eliminate or minimize so far as possible the actionof centrifugal force on the body of paste compound contained in cup or reservoir I when the latter is rotated at high speed. These bores I2 of the reservoir or cup ID and grinding or cone member 9 are so disposed with respect to the notches I3 that as assembled on the shaft I the bores I2 of the cup or reservoir I0 and the bores I2 of the grinding or cone member 9 will be substantially in full registry to form continuous grinding or lapping paste compound discharge conduits or channels I2 leading from the lower portion of the interior of the cup or reservoir I0 through the medial or central portion of the cone grinding face of the grinding or cone element 9 so as to discharge the grinding compound directly between the narrow face of the Valve seat being ground and the opposing narrow zone portion of the grinding cone, the construc tion being such that it is impossible to clamp the cup I0 and grinding or cone element 9 in operative position on the shaft I without getting the bores I2 of cup Ill and the bores I2 of grinding or cone element 9 in proper registering relationship.

A plunger or piston II applied over the upper end of shaft I is formed with a smooth axial bore extending centrally and axially from its lower end for a part of its length and of such diameter as to slidingly snugly receive the smooth unthreaded cylindrical portion of shaft I between thread 'I and shoulder 2 and has its upper portion formed with slightly smaller coaxial internally screw-threaded bore to engage and cooperate with the screw-thread 1. The lower end portion of this plunger or piston is preferably three one thousandths of an inch less in diameter than the internal diameter of the cup or reservoir II! into which it moves to give sufficient clearance between the outer peripheral face of the plunger or piston II and the opposed inner peripheral face of the cup or reservoir I0 to avoid binding or freezing of these two parts together by the action of the gritty grinding or lapping paste compound material normally contained in the reservoir Ill.

To prevent the body of the paste compound from working up between the opposing peripheral faces of the piston or plunger II and the reservoir or cup II! as the former is moved into the latter and also to exert a continued compressing, shoving or expelling action on the paste body after a feeding adjustment of the plunger I I has been completed, a relativelythick leather, rub ber or similar material washer or disc I6 is secured against the bottom face of the plunger or piston II by means of a relatively thin sheet steelwasher or plate I5 held against the lower face of the cushioning washer I6 by any suitable means, as by screws II extending through washer I5, washer I6 and into screw-threaded bores in the piston or plunger II and being turned home a sufficient degree to hold the plate or washer I5 in contact with the lower face of the cushioning compressible and expansible washer I6 when the latter is in its fully expanded condition and not being turned up to such an extent as would compress the washer I6, whereby the latter may gradually expand to its normal condition after having been compressed between the thrust of the piston or plunger I I on the body of the paste ness and approximately twelve thousandths of an inch less in diameter than the diameter of the lower end of the plunger or piston II so as not only to avoid binding in the cup or reservoir II] but also to permit some slight bending and flexing of the leather washer I6 inward beyond the edge of the lower end of the piston or plunger I I.

Preferably in the embodiment illustrated the cup or reservoir III will have an interior diam eter of 1 inches and a cavity depth of inch and will have its upper inner peripheral edge formed with a short bevel to facilitate the entry of the leather washer I6 therein; the lower end of the plunger or piston II will be 1.477 inches in diameter; the washer I5 will be approximately 1.465 inches in diameter; the holes or conduits I2 will be approximately 3 sixty-fourths of an inch in diameter; and the leather washer IE will be of such diameter as to make a snug sliding fit in the peripheral wall of cup I0.

The screw-thread 1 extends for such distance, as shown, that the plunger or piston II may be screwed down the same until the plate or washer I5 come into engagement with the lower inner face of the cup or reservoir II] with a light contact or almost into such engagement, it being desirable, however, that such endwise movement should not be permitted to such extent as would permit these faces to be brought into firm or compressing or crushing contact as in view of the frictional action of the contained gritty material the parts might become locked or frozen and to this end the thread 'I will preferably be of such length as Will permit the plate or washer I5 to approach very close to'the bottom of the reservoir or cup II] but yet will not permit it to come into actual contact therewith.

In operation the tool being assembled and loaded with grinding or lapping paste compound,

the upper end portion 3 is inserted in the bore of an adapter I8 and clamped in position therein by a set screw 20, or secured in the chuck of a small electrically driven or other motor driven apparatus, the lower portion of shaft I is then inserted down through the valve seat through the usual valve stem guide or bushings, the knurled or grooved outerperipheral face of the cup, I0 is then gripped firmly with one hand and the plunger or piston II, which may have a squared upper end portion as shown, is gripped with the other hand and given a very slight partial rotary movement, causing a slight axial movement of the plunger into the cup or reservoir I0, the large effective area of the plunger II in comparison to the small diameter of the two discharge conduits I2 causing a compression of the leather or rubber or similar material washer I6 which in thereafter expanding continues to expel the grinding paste through the discharge conduits ata fairly uniform gradually decreasing rate of discharge, such continual renewal of sup! ply not only insuring suflicient supply of abrasive material at all times to the narrow conical band portion of the seat being ground, which band is usually quite narrow, being hardly more than a blunt edge, in comparison to the oldvalve seats integral with and reamed, or countersunk, in, the engine block, but also keeping all of the grinding paste theretofore supplied to said surfaces. moist or wet and so preventing the blowing about of any gritty dust from the job.

The shaft I will preferably be approximately seven and three thirty-seconds of an inch in overall, length with its lower reduced diameter portion approximately three and five eighths of an inch in length and five sixteenths'of' an inchin diameter so as to fit down in or through, and be centered by, the usual valve stem giudes or bushings in accordance with well known practice.

By making the cup or reservoir l0 and the grinding element or cone 9 as separate parts it is practical to make the cup or reservoir I0 of brass by diecasting at a very material economy of manufacture over turning it out of bar stock or forming it by other casting operations, whereas such die-casting of the grinding element or cone 9 would not be suitable, at least according to the present development and limitations of die-cast ing so far as known to applicant inasmuch as it is diflicult to extract the air from the die and as the walls increase in thickness the air becomes trapped, making them increasingly porous in accordance with the increase in thickness of walls, such porosity rendering the casting defective for such grinding purposes, and accordingly the grinding element or cone 9 is preferably produced by turning it out of bar stock. Thus by making reservoir l0 and cone or grinding element 9 separately I am able to achieve a substantial economy of manufacture of the cup or reservoir ID in combination with retention of the advantages of a substantially homogeneous non-porous grinding element or cone 9.

The length and details of form of the shaft lware not essential and such matters may be changed and varied in a number of different ways to suit the shaft to any other embodiment of the broad invention that may beselected or determined upon by anyone.

-While it is preferred that the reservoir l0 and the grinding element or cone 9 be made as separate detachable and removable parts, for the reasons stated, this is not essential.

While the means of forcing or feeding the grinding or lapping paste from the reservoir I0 is preferred this is not essential and any means whatsoever-of any nature capable of performing the function broadly stated of feeding the abrasive material in any manner so that it will be delivered in'any way, directly or indirectly, to the surface being acted upon will suffice.

-While the co-axialarrangement of the reservoir with the shaft l is preferred this is not essential, it sufiicing if there be some means definitely associated with and constituting-a part of a unitary tool or apparatus for this purpose, such means being capable of holding a supply of abrasive material and of feeding or'delivering the same to the surface being acted upon.

While the use of a moist, or wet or paste form abradant is preferred and is made practical by this invention, this is not essential.

While the number, form, location, and general disposition and direction of the conduits or channels I2 illustrated and described are preferred, .all such considerations are mere matters of detail notessential to the broad'concept of my invention and may be departed from and varied in a great many different'ways-so long as their broad general feeding or abradant delivery function is served in some Way.

While'the grinding element 9 has been described above as having a conical grinding face and also has been referred to as a grinding cone, it has been so illustrated, described and referred to simply because that happened to be its form in the embodiment illustrated for use on cone form valve seats. However, it is to be understood that the detail form or profile of the grinding portion of the grinding element will vary according tothe form of the valve seats on which a given grinding element is to be used, for instance. where flat seats are to be ground, a grinder with a plane or flat radial face would be used. The exact form or profile of the grinding portion of the grinding element is not material to, and forms no essential part of, my present invention, it being understood that a grinding element of suitable form will be used on a given grinding job.

Having thus described my invention, what I claim as newand desire to secure by Letters Patent is:

1. A seat grinding tool comprising a shaft, a cup shaped container member having an -open upper end and formed with a central perforation in its bottom to snugly slidably receive a portion of said shaft, -a grinding element having a central perforation in its top to snugly slidably receive a portion of said shaft, the walls of said perforations and said portion of said shaft being so formed as to interlock and prevent relative rotary movement between said shaft said container and said grinding element and to prevent relative rotary movement between said container and said grinding element, said container being adapted to contain a fluent abradant, stop means on said shaft to'engage, the upper face'of the bottom of said container to prevent axial movement thereof in one direction, and a nut engaging saidshaftand acting to force said container against said stop means and said grinding element against said container'to clamp said 'container and'grinding element on said shaft portion against axial movement, said container and said grinding element each being formed with a plurality of small axial bores, the respective bores of the container registering in an-axial direction with the respectivebores of said grinding element in the assembled relation of said container and said grinding element and constituting aplurality of composite discharge conduits extending substantially parallel to the'axis of said shaft from the extreme radiallyouter portion of the interior of said container through the grinding face of said grinding element, in combination with a piston having screw-thread engagement with'said shaft above said container and comprising a 'lower'portion adapted to rotate about said shaft and'to move into said container to force abradant therefrom through said conduits, a compressible and expansible washer applied to the lower end'of'said piston and extending radially outwardly beyond and below said lower end portionof said piston to make a snug fit in said container, and means for securing said washer to said piston while leaving it free to be compressed between the thrust of' said piston and the resistance of the body of Jabradant and to act thereafter by its expansion to continue to force abradant from said container through said conduits.

2. A seat grinding tool "comprising a shaft, a

container having an open upper end and formed with a perforation in its bottom to slidably receive a portion of said shaft, a grinding element having a perforation in its top to slidably receive a portion of said shaft, means for preventing relative rotary movement between said shaft said container and said grinding element, said container being adapted to contain a fluid or fluent abradant, and means for detachably securing said container and said grinding element together against relative axial movement, said container and grinding element each being formed with a bore, said bores registering in an axial direction in the assembled relation of said container and said grinding element and constituting a continuous composite conduit extending from the interior of said container through the grinding face of said grinding element, in combination with a piston having screw-thread engagement with said shaft above said container and comprising a lower portion adapted to rotate about said shaft and to move into said container to force abradant therefrom through said conduit, a compressible and expansible member applied to the lower end portion of said piston, and means for securing the compressible and expansible member to said piston while leaving it free to be compressed between the thrust of said piston and the resistance of the body of abradant and to act thereafter by its expansion to continue to force abradant from said container through said conduit.

3. A seat grinding tool comprising a shaft, a container having an open upper end and formed with a perforation in its bottom to slidably receive a portion of said shaft, a grinding element having a perforation in its top to slidably receive a portion of said shaft, means for preventing relative rotary movement between said shaft said container and said grinding element, said container being adapted to contain a fluent abradant, and means for detachably securing said container and said grinding element together against relative axial movement, said container and said grinding element each being formed with a small bore, said bores registering in an axial direction in the assembled relation of said container and said grinding element and constituting a composite discharge conduit extending from the interior of said container through the grinding face of said grinding element, in combination with a piston, means for forcing said piston into said container, resilient compressible and expansible means applied to the lower end of said piston and extending radially outwardly beyond and below said lower end portion of said piston to make a snug fit in said container, and means for securing said compressible and expansible means to said piston while leaving it free to be compressed between the thrust of said piston and the resistance of the body of abradant and to act thereafter by its resilient expansion to continue to force abradant from said container through said conduit.

4. A seat grinding tool comprising a shaft, a fluent abradant container formed with a perforation in its bottom to slidably receive a portion of said shaft, a grinding element having a perforation in its top to slidably receive a portion of said shaft, means for preventing relative rotary movement between said shaft said container and said grinding element, and means for detachably securing said container and said grinding element together on said shaft against axial movement with relation to each other and to said shaft, said container and said grinding element each being formed with a bore, said bores registering in an axial direction in the assembled relation of said container and said grinding element and constituting a continuous composite conduit extending from the interior of said container through the grinding face of said grinding element, in combination with means for forcing abradant from said container through said conduit.

5. A seat grinding tool comprising a shaft, a container mounted on said shaft to turn therewith, and a grinding element mounted on said shaft to turn therewith, said container and said grinding element being formed with discharge conduits forming communication between the interior of said container and the grinding face of said grinding element in combination with a plunger movable into and from said container and having engagement with said shaft, and compressible and expansible means carried by said plunger for continuously forcing a fluent abradant from said container through said conduits during a grinding operation.

HARRY W. KULP.

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