US2645887A

US2645887A - Valve stem grinding machine

Info

Publication number: US2645887A
Application number: US105418A
Authority: US
Inventors: Harry E Miller
Original assignee: Individual
Current assignee: Individual
Priority date: 1949-07-18
Filing date: 1949-07-18
Publication date: 1953-07-21
Anticipated expiration: 1970-07-21

Description

H. E MILLER 2,645,887

VALVE STEM GRINDING MACHINE July 21, 1953' 4 Sheets-Sheet 1 Filed July 18, 1949 III 5 W21 I I cLEARAm: H

y 21, 1953 'H. E. MILLER 2,645,887

I VALVE STEM GRINDING MACHINE Filed July 18, 1949 4 Sheets-Sheet 2 fig. 2

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July 21, 1953 H. E. MILLER VALVE STEM GRINDING MACHINE 4 Sheets-Sheet 3 Filed July 18, 1949 July 21, 1953 H. E. MIL-LER VALVE STEM GRINDING momma:

Filed July 18, 1949 I LEARANCE. r-

Patented July 21, 1953 'oFFIcE VALVE .STEM GRINDING MACHINE Harry E; Miller, Buffalo, W. Va. I Application July 18, 1949, Serial No. 105,418

1. The present invention relates to grinding machines, and more especially, to a new and improved valve stem grinding machine of simple and practical form which maybe effectively operated by comparatively unskilled operators, while assuring precision grinding operations.

Most internal combustion engines are equipped with tappet valves to control the inlet of fuel and the exhaust of gases in the combustion chamber or chambers of the engine. Inthe course'of normal operation of the engine, the valves and valve seats ultimately become burned and distorted, thereby reducing the compression and the power output of theengineas a consequence of the imperfect seating or sealing of the valves. Accurate seating or sealing of the valves is particularly important in modern internal combustion engines of the so-called highcompression type, so when burning or distortion of the valves or valve seats occurs, it becomes necessary to remove the valves and re-face the 9Claims. (clef-124) same as well as to machine the seats to match the re-faced surfaces of thevalves which must accurately fit the seats to insure a gas-tight seal under the usual relatively high pressures and temperatures which prevail in such engines.

In the original surfacing or subsequent resurfacing and machining of the valves and valve seats, the effective length of the valve stems is increased, and hence it becomes necessary, particularly in the case of engines having nonadjustable tappets, to shorten the valve stems, which is usually done by grindingoff the free end of each valve stem, that is, the end which contacts the tappet orlifter, with due allowance for expansion of the valve under operating temperatures. and the tappet when the valve is seated should be The clearance between the valve stem accurate and uniform for all valves of the engine to within about one-thousandth of an inch to insure complete seating of the valves, smooth running of the engine and absence of noise of the valves.

The present invention has been developed to curate and more fool-proof performance t a the prior grinding'machineswhich have been available heretofore, with less skill required to perform avery-precise grinding job. A further object of the invention is to provide an improved valve grinding machine which in cludes a movable valve holder in which the adjustable gauge bar, according'to the required length of-the valve stem.

Another object of the invention is to provide a grinder as describedin the preceding paragraplnwherein the depth gauge or gauge bar constitutes an adjustable stop member, andv directly coacts with a fixed stop member or abutment during the grinding of the valve stem, and positively limits the amount of the stem which can be ground off for any given or preselected setting of the depth gauge or gauge bar.

Theinvention still further contemplates the provision of adjustable truing or facing means for truing or facing off the grinding surface of the rotary grinder or abrasive wheel, whenever desired or required, while maintaining aconstant relationship of the fixed stop member or abutment and the operative face of the grinding S111? face of the abrasive wheel, so as to always insure the attainment of the required length of the fin-- ished valve stem without necessitating'adjustment or re-adjustment of the limit stop, once it has been set for the desired clearance, no matter how many times the grinding surface is faced or trued.

7 Other and further objects and advantages of the invention will be hereinafter described and the novel features thereof defined by the appended claims In the drawings:

Figurel is aview in top plan of a valve stem grinding machine constructed in accordance with ,my invention and showing. a valve stem mounted therein l and disposed inythe grinding position, witha portion of the valve holder broken away and shown in section;

Figure 2 is a view of the machine in sideelevation, as observed on looking towards the right .hand end of the machine in Figure 'lgj Figure 3 is a vertical sectional view taken on the line 33 of Figure l, andmoreparticularly showing the cooperation of the depth gauge or "adjustable gauge bar with the fixed limit stop or abutment, which predetermines and controls the amount of material which may be ground off the valve stem for a selected or given setting of the depth gauge;

Figure 4 is a detail view in perspective of the movable valve holder;

Figure 5 is another detail view in perspective of the frame of the dressing or truing fixture;

Figure 6 is a view in top plan :of the mounting sleeve or support on which the dressing or truing fixture is slidably mounted and in which the valve holder is slidably and pivotally mounted;

Figure 7 is a fragmentary detail view of the mounting sleeve of Figure 6, with the sleeve shown partly in section and partly in elevation;

Figure 8 is a detail view in perspective and on a somewhat reduced scale, of the base of the machine, and particularly showing the motor mounting saddle and the supporting standard for the fixed mounting sleeve of Figures 6 and 7;

Figure 9 is a fragmentary view in front elevation, showing in full lines the normal position of the valve holder during grinding of the valve stem, while showing in broken lines other positions of the valve holder as assumed in pivotally swinging the holder upwardly and downwardly;

Figure 10 is a fragmentary vertical sectional view through a conventional engine block, and showing in elevation the depth gauge or adjustable gauge bar in position and set to the measurement of the distance from the valve seat to the tappet or lifter, as required preliminary to transfer of the depth gauge to the grinding machine for controlling or limiting the grinding of the valve stem;

Figure 11 is a view generally similar to Figure l, but showing a modified form of adjusting means for the dressing or truing fixture, with certain parts of the machine broken away and shown in section; and

Figure 12 is a sectional view as taken on the line I2I2 of Figure 11.

Like reference characters designate corresponding parts in the several figures of the drawings, wherein I denotes the base of the machine, said base having any suitable form and size, but preferably being made from a suitable metal casting to provide a relatively flat base plate 2 having a motor-mounting saddle 3 integrally formed therewith and extending upwardly from the upper face thereof near one end, and an upright standard or support 4 also integrally formed therewith and extending upwardly from the upper face thereof near the opposite end. The standard or support 4 is suitably braced and reinforced by webs 5, as will be readily apparent from reference to Figures 1, 2 and 8.

Mounted on the saddle 3 and suitably secured to the base I in any desired manner, is an electric motor 6 or other appropriate prime mover the upper side of the tubular part or hub I4 and which carries and drives a rotary grinder or abrasive wheel 'I of any suitable type,. said abrasive wheel being preferably mounted on the free end of the motor shaft as indicated at 8. In the drawings, the abrasive wheel I is shown in the form of a conventional cupped wheel which presents an operative grinding face 9 of annular form at the front side thereof.

It will be further seen from the drawings that the standard or support 4 is provided at its upper end with a transversely extending bore I0 running completely therethrough from the front to the back thereof. In this bore is snugly and rigidly fitted a tubular supporting sleeve 1 I which is suitably fixed to the standard 01. Support 4 integrally formed therewith is a transversely extended channel I5 in which is mounted a bar ,IS of generally rectangular form, which bar is free to slide transversely to the right or to the left as seen in Figure l of the drawings. The channel I5 is provided with a removable cover plate I1 which is preferably secured in place by suitable screw fastenings I8.

At one end of the bar I 8, namely, the left-hand end as viewed in Figure l, a dressing tool, preferably having the form of a diamond point I9 is mounted on the bar, said diamond point being preferably adjustable forwardly and rearwardly, as by means of a threaded shank which is screwed through a corresponding threaded opening extending through the bar I6. Adjustment of the diamond point I9 may be effected conveniently through the provision of a screw driver slot 20 in the front end of the shank of the diamond point.

The end of the bar I6 opposite to the end which carries the diamond point I 9, is suitably connected to a cross feed screw 21 or other appropriate operating device for imparting endwise movements in opposite directions to the bar I6, with consequent crosswise movements of the diamond point I9. In order to establish the connection between the cross feed screw 2i and the bar I6, permitting rotation of the screw 2I while confining movements of the bar I6 to endwise movements, the end of the bar I6 is notched or slotted at one side to receive an enlarged circular head 22 on the inner end of the cross feed screw 22, said head 22 being free to rotate in the slot or recess in the bar I6, as more particularly illustrated in Figure 11 of the drawings. A threaded cap bushing 23 is fixed to the adjacent end of the housing or frame of the dressing fixture, and serves to keep the cross feed screw 2| in axial alignment with the bar Iii. The outer end of the cross feed screw 2I is fixed to a hand-crank 24 'or other operator to facilitate rotation of the cross feed screw in manipulating the diamond point I9 back and forth across the operative face of the abrasive wheel I to dress off or true the operative face of the grinding wheel.

Feed of the dressing fixture to move the diamond point I9 towards and away from the face of the abrasive wheel to be dressed, and to control the amount of material which is dressed off the abrasive wheel during the dressing or truing-operation, is attained by means of an adjusting screw 25 or other appropriate ins'trumentality, as shown in Figures 1 and 2. In this form of the adjusting instrumentalities, the screw 25 is provided at one end with an enlarged operating head or knob 26, and the screw extends through a laterally extended, bifurcated boss or ear 27 on the frame of the dressing fixture I3, with suitable thrust washers 28, 28 pinned or otherwise secured to the screw 25 at the front and back respectively of the boss or ear 27, so that the screw cannot shift forwardly or rearwardly relative to the boss or to the dressing fixture as a whole. The rear end of the screw 25 is suitably threaded as at 29 and is threadedly engaged in-a threaded opening extending through a lateral boss or lug 30 integrally formed with and projecting laterally from one side of the standard or support 4. Thus, by rotating the screw 25 in one direction or the other, the dressing fixture I3 as a whole may be adjusted forwardly or rearwardly as required.

In order to positively lockthe'dressing fixture I3 in any position of its forward or rearward adjustment, a locking screw 3| is preferablyprovided, the shank of the locking screw being threaded through the tubular part l4 of the frame of the dressing fixture I3, at the front of the cross channel l5, so that the extreme lower end of the locking screw 3! may be screwed tightly against the upper side of the fixed supporting sleeve H on which the dressing fixture is slidably mounted. the locking screw thus acting similar to a set screw.

To facilitate guiding of the'dressing fixture in its forward and rearward adjustments on the fixture in its forward and rearward adjustments on the fixed supporting sleeve II, and to relieve the adjusting screw 25 from any undue strains thereon as the result of any tendency of the dressing fixture to rotate on the fixed supporting sleeve H during the dressing or truing of the abrasive wheel I, the upper side of the supporting sleeve I I is preferably provided with an axially extended, shallow groove or recess 32 in which the extreme lower end of the locking screw 3! is received and is free to slide when the locking screw is released sufficiently to permit forward and rearward movements of the dressing fixture.

Continuing reference to Figures l to 8 inclusive of the drawings, it will be further seen that the frameof the dressing fixture I3 is provided at its rear with a pair of laterally spaced ears or

lugs

33, 33, the same being formed as an integral part of the frame and extending upwardly from the tubular part of the frame, as well as rearwardly from the cross channel [5 of the frame. Suitably fixed between the lugs or

ears

33, 33 and snugly fitting therein is a stop member 34. In order to rigidly and securely hold the stop member in position, I preferably employ a plurality of removable dowels 35 extended through the

ears

33, 33 and the intermediate stop member, together with a central anchor screw 36 likewise extending through these parts.

As best shown in Figure 3 of the drawings, the stop member 34 extends downwardly through an axially elongated slot 31 formed in the upper side of the fixed supporting sleeve II, with the lower end of the stop member34 terminating in abutting contact with the lower inner face. ofthe supporting sleeve ll. i Y 1 The stop member 34 is preferably of uniform thicknessfrom top to bottom thereof, corresponding to the dimension between the lugs or

cars

33, 33 between which thes'ame'is mounted, so that the stop member can be inserted through the slot 31 in the fixed sleeve H and fastened to the ears or lugs 33, 33 after the dressing fixture has been slipped onto the supporting sleeve and moved rearwardly therealong until the ears 33, 33 :are disposed over the slot 31. It will be of the spring as 'is' disposed to yieldin gly' engage the rear end of a tubular mounting armor sleeve 40 of a Work holder or'valve holder generally indicated at 4| and shown in detail in Figure 4. The armor sleeve 40 is accurately fitted in the for ward end of the fixed supporting sleeve 'l l, but

is free to slide forwardly and rearwardly 'in the latter, as well as free to turn orpivot therein. At the forward end of the arm or sleeve 40, an annular enlarged head 42 is provided thereon,

said head being formed with an accurately 46'corresponding'to the seat 43 and to the valve seatof the engine. Rearwardly extended from the back of the head '45'and disposed parallel,

to the arm or sleeve 40 is an arm having a groove or channeL'preferably /-shaped in cross-section, formed therein, said arm being designated 41, and the groove or channel being designated 48. The groove or channel 48 is so positioned in relation to the se'at 46' in the annular head of the valve holder, that when a valve is mounted in the holder in the manner shown in Figure 1 of the drawings, as indicated at 49, the valve stem 50 will be supported by the arm 41 for a substantial part of its length, while-the valve head 5| is fully and accurately seated on the seat 46, with the opposite or tappet end of the valve extended rearwardly from the valve holder and free to be engaged with the operative grinding surface of the abrasive Wheel 1 of the'grinding machine, when the valve'holder is pushed rearwardly and swung through an arc to move the free end of the valve stem across the operative face of the abrasive wheel, as generally represented in-broken lines in Figure 9 of the drawings. To facilitate manipulation of the valve holder, a finger-piece 52 is laterally extended from the side of the arm '41, said 'fingerpiece to be engaged by the middle finger of the left-hand of the machine operator, with this finger extended over and behind the fingerpiece 52, while the forefinger of the same hand front face of the valve head 5|.

In order to predetermine the amount of material which is to "be ground off the valve stem in any given instance, and in order to control or'limit with the necessary degree of accuracy the amount of material ground off the stem during the grinding operation, there is used with the grinding machine a depth gauge, or an adjustable gauge bar which serves both to measure the distance from any valve seat to the tappet I in the engine for'which the valves are'to be further seen from reference to Figure 3 that the ground, as well as constitutes a limit stopin cooperation with the stop member .34 hereinbefore described. Thus, the depth gauge or adjustable gauge bar constitutes an operative part of the grinding machine during the'grinding operation, which is a substantial "and-an important difference from machines heretofore employed for valve stem grinding operations. j

The depth gauge or adjustable gauge bar'is generally indicated at 53 in the drawings, and

the'details thereof will be. best. understood from access? reference to Figures 1, 3 and 10, from which it will be observed that the depth gauge includes a tubular barrel 54 having an enlarged head 55 formed on the outer end thereof which is interiorly threaded for threadedly engaging the outer threaded end of a cylindrical bar or pin 56 which extends completely through the barrel 54 and is rotatable therein by turning the knurled outer end 51 of the bar to axially project the inner end of the bar 56 to a more or less extent from the inner end of the barrel. A locking screw or set screw 58 extending through the head 55 into engagement with the bar 56 serves to permit the bar to be locked or restrained against accidental movement when adjusted in the manner just described.

Axially spaced inwardly from the head 55 and formed on the barrel 54 is an annular flange 59 having its inner face beveled to correspond with the bevel of the valve seat in an engine block and with the beveled seats 43 and 46 respectively of the valve holder or work holder 4|. If desired, either or both of theseats 43 and 46 may have the form of hardened annular inserts, as indicated more particularly at 43' in Figure 3, thereby minimizing wear and damage of the seats over long periods of use of the machine.

In adjusting and setting the depth gauge or adjustable gauge bar 53, it is first inserted in the place of the valve after removal of the valve from the motor block, as indicated at 60 in Figure 10, the valve seat in the motor block having previously been machined or 're-finished so that it is ready for assembly or re-assembly of the valves in the engine. The beveled shoulder 59 on the barrel 54 of the depth gauge will thus seat upon the valve seat, and when so seated, the bar or pin 55 is rotated in the appropriate direction until the inner end of the bar or pin 56 touches the upper face of the tappet or lifter 52, the latter being controlled by the usual cam 63 which forms a part of the valve operating mechanism of a conventional internal combustion engine. When the bar or pin 55 has been so adjusted, the locking screw 58 is then tightened so that the depth gauge can be handled and removed from the engine block without danger of disturbing. the adjustment which now conforms exactly to the distance from the valve seat 5| to the valve tappet 62 of the engine, as measured by the corresponding distance from the beveled shoulder 59 of the depth gauge to the inner endof the bar or pin 55.

The depth gauge is now transferred from the engine block and inserted into the 'arm or sleeve 49 of the valve holder or work holder 4| of the valve stem grinding machine, the depth gauge being moved rearwardly into the sleeve 40 until the beveled shoulder 59 seats fully on the seat 43. The machine is now ready for grinding a valve stem to fit the engine according to the measurement as determined .by the depth gauge in the manner just described. Accordingly, a valve is then placed in the valve holder 4|, with the valve head fully seated against the seat 46 and held in such position in the manner previously described, the operator employing his left-hand to hold the valve head 5| against the seat '45 and to manipulate the valve holder, while at the same time pressing with his right-hand against the outer or forward end of the depth gauge, thereby moving the depth gauge and the work or valve holder together ina rearward direction, against the yielding pressure of the spring 39 which engages the inner end of the sleeve or arm 40 of the valve holder 4|. This inward movement and pressure is continued and is preferably accompanied by an upward and downward rocking or swinging movement of the valve holder about the axis of the sleeve or arm 40, so as to avoid undue wear of the operative or grinding surface of the abrasive wheel I at any one point or at any given area, while at the same time insuring an even, smooth flat surface on the end of the valve stem as it is being ground off. The grinding operation is continued until the inner end of the bar or pin 56 comes into abutting engagement with the forward face 64 of the stop member 34, said face 64 being in vertical alignment with the forward face of the portion of the stop member 34 which projects upwardly through the slot 31 in the fixed supporting sleeve H, and abuts against the rear face of that portion of the frame of the dressing fixture in which the cross channel I5 is formed. When the bar or pin 55 engages the face 64 of the stop member 34 in the manner just described, no further inward or rearward movement of the valve holder is possible because of the limiting action of the cooperating stop members, and the grinding of the valve stem is thus completed so that the length of the valve from the beveled head to the tappet end of the valve stem would exactly correspond with the distance from the beveled shoulder 59 to the tip or inner end of the bar 56, but for a variation to allow for sufficient clearance necessitated by expansion of the valve due to the normal operating temperatures of the engine in which it is installed. When the operator releases his pressure against the valve and against the depth gauge at the completion of the valve stem grinding operation, the spring 39 will automatically expand slightly and push forwardly against the inner end of the sleeve or arm 40 of the valve holder 4|, thus urging the valve holder, together with the finished valve away from the rotary grinder or abrasive wheel I, whereupon the valve may be removed from the valve holder and is ready for installation or re-installation in the valve chamber of the engine for which it was particularly ground to fit. It will be understood, of course, that before the valve stem is ground in the grinding machine as above described, the valve head will be machined or re-finished to exactly fit the valve seat SI of the engine, and that unless the valve stem is ground ofi, according to the measurements determined by the depth gauge, the valve stem would be too long.

In order to obtain the necessary clearance to allow for expansion of the valve during operation in the engine, the valve stem is ground slightly shorter than the measurement for which the depth gauge is initially set in the engine block. This clearance is taken into account in the grinding machine by setting the diamond point I 9 somewhat ahead or forwardlyof the plane of the front face of the stop member 34 and its effective depth gauge abutting face 64, to a more or less extent, according to the amount of clearance desired. The setting of the diamond point to conform to the desired clearance is best illustrated in Figure 11 which is generally similar to Figure 1, excepting for the adjusting instrumentalities which serve to adjust the forward and rearward movements of the dressing fixture and diamond point. As will be observed from Figure 11, the rear face of the channeled .9 part of the frame of the dressing or truing fix ture I3, is ground back for a distance or to an extent equal to the desired clearance as represented by the opposed arrows in this figure. In grinding off the frame in the manner just mentioned, a sufficient area is removed so as to aiford a flat, true surface of substantial size, which is parallel to and somewhat forward of the forward face of the stop member 34 and the latters stop surface 64. A fiat .block or other appropriate gauge or bar, indicated in broken lines at 55, may then be laid or held flat against the ground oif and flattened surface ,66 of the frame of the dressing fixture, as shown in Figure 11, and then the diamond point [9 is adjusted forwardly or rearwardly by rotating the screw shank thereof until the diamond point touches and is flush with the forward face of the gauge block or bar 65. If any variation of the clearance is desired from that which is attainable by setting the diamond point in the manner just described, a feeler gauge can be placed between the setting gauge block or bar 65 and the ground off surface 66, which will result in reducing the valve clearance and produce a longer valve stem at the completion of the valve stem grinding operation. On the other hand, by placing a feeler gauge between the setting block or gauge 65 and the diamond point, this would increase the valve stem clearance and produce a shorter valve stem at the completion of the valve stem grinding operation. This is due to the fact'that once the diamond point is adjusted with the aid of the setting block and/or feeler gauge, as above described, and the abrasive wheel 1 is faced off or trued by moving the diamond point across the operative face of the abrasive wheel by means of the cross feed screw 2|, accompanied by a forward or rearward movement of the entire dressing fixture by means of the adjusting screw 25, as may be necessary to completely true or face off the operative face of the abrasive wheel, the distance from the trued face of the abrasive wheel to the valve head seat 46 of the valve holder M at the end of each grinding operation will always equal the distance from the operative stop face 64 of the stop member 34 to the beveled shoulder 59 of the depth gauge 53, less the clearance determined by the setting of the diamond point. Once the diamond point is set and remains in the same relative position to the stop 34, the same clearance will be maintained or produced for every valve no matter how often the abrasive wheel is trued or faced off, or how much of the abrasive wheel is removed during the I truing or dressing operation, except of course for wear of the diamond point, which is inappreciable and immaterial. This same clearance is also maintained for every valve no matter what the setting of the depth gauge or gauge bar is, and I i no matter how long or how short the valve stem should be to fit the engine properly.

It has been found in actual use of my valve stem grinding machine that it is ordinarily possible to grind off the stems of from six to eight sets of valves before it is necessary or desirable to true or face off the abrasive wheel or rotary grinder, and even then, the dressing off becomes advisable only because the interstices of the abrasive material of the grinding wheel have become filled up with metal, and the grinding wheel should be dressed to restore the effective grinding surface to the best condition consistent with efficient and good workmanship.

In the modified arrangement shown in Figures 11 and 12, the construction and arrangement of the machine is generally similar to that described in .the foregoing, and the parts are similarly identified by the same reference characters, ex'- cept for the instrumentalities for adjusting the dressing or truing fixture in a forward and rearward direction upon the fixed support or sleeve II. In the modified construction, the screw 25 as well as the locking screw 3|, are both elimi= nated, and in lieu thereof, a pin or bar 61 is suit ably attached to the rear face of the stop member 34 and the bar or pin 61 is extended rearwardly through the fixed supporting sleeve ll, coaxially therewith, to a point somewhat beyond the rear end of the sleeve I l. The rear end of the sleeve II is interiorly threaded, and threadedly receives a sleeve nut 68 having an enlarged head or knob 69 formed on the rear end thereof, the knob being provided with a central opening through which the pin or bar 61 extends. The outer end of the pin or bar 61 is threaded, as at 10, for threaded engagement with a locking nut II which serves to permit an annular flange 12 on the pin or bar 61 to be clamped tight against the inner face of the nut 69 when the nut H is tightened up against the outer face of the nut 69. In order to permit and cause movement of the dressing or truing fixture 13 in a forward or rearward direction, the nut H is loosened slightly, whereupon the nut 69 may be rotated in one direction or the other to cause movement of the entire dressing fixture assembly pursuant to the action of the screw threads on the inner surface of the fixed supporting sleeve II, which engage the sleeve nut 68. After appropriate adjustment of the dressing fixture, the locking nut H may be re-tightened against the nut 69 to rigidly hold the dressing fixture in position. Otherwise, the operation of the modified construction is precisely the same as hereinbefore described. I

No further description of the construction and operation of the machine will be necessary herein, in view of the foregoing, and it will be obvious from the drawings and the accompanying explanation that my new valve stem grinding machine is of exceptionally simple and practical form, and may be effectively operated by comparatively ,unskilled operators, while assuring precision grinding operations. Under normal circumstances, no reading of gauges or other complicated instruments is necessary in the use and operation of my new machine, yet the machine is capable of producing any desired clearance and uniformly maintaining such clearance no matter how often or how much the grinder or abrasive wheel is trued off or dressed.

While the specific details have been shown and described herein, the invention is not confined thereto as changes and alterations may be made without departing-from the spirit thereof as defined in the appended claims.

I claim:

1. A valve stem grinder for grinding the'tappet ends of the stems of tappet valves, comprising a support, a rotary abrasive grinding wheel carried by said support, a valve holder movably mounted on said support adjacent to said abrasive wheel and shiftable towards'and away therefrom, said holder having a valve-supporting portion and a depth gauge-supporting portion, in spaced relation to each other, each of said supporting portions having a seat, one of which seats is adapted to be engaged by the head of a valve during the stem-grinding operation, with the stem projecting towards the abrasive wheel, an adjustable depth gauge removably seated upon the other seat of said valve holder during the stem-grinding operation and movable with said holder, said depth gauge having an inner end projecting inwardly from the seat in the depth gauge-supporting portion in parallel relation to the valve-supporting portion, and a relatively fixed abutment carried by the first-mentioned support for abutting engagement with the inner end of said depth gauge to limit the movement of the holder and the valve being ground according to any pre-selected setting of the depth gauge in the valve position in an engine to the measurement from the valve seat to the tappet of the engine, said valve holder including a hollow supporting member axially extended from one side of the depth gauge engaging seat, said supporting member being slidably mounted in a fixed support carried by said first-mentioned support, with the inner end of said depth gauge extended coaxially through the hollow supporting member of the holderv 2. A valve stem grinder for grinding the tappet ends of the stems of tappet valves, comprising a support, a rotary abrasive grinding wheel carried by said support, a valve holder movably mounted on said support adjacent to said abrasive wheel and shiftable towards and away therefrom, said holder having a valve-supporting portion and a depth gauge-supporting portion in spaced relation to each other, each of said supporting portions having a seat, one of which seats is adapted to be engaged by the head of a valve during the stem-grinding operation, with the stem projecting towards the abrasive wheel, an adjustable depth gauge removably seated upon the other seat of said valve holder during the stem-grinding operation and movable with said holder, said depth gauge having an inner end projecting inwardly from the seat in the depth gauge-supporting portion in parallel relation to the valve-supporting portion, and a relatively fixed abument carried by the first-mentioned support for abutting engagement with the inner end of said depth gauge to limit the movement of the holder and the valve being ground according to any pre-selected setting of the depth gauge in the valve position in an engine to the measurement from the valve seat to the tappet of the engine, said valve holder including a hollow supporting member axially extended from one side of the depth gauge engaging seat, said supporting member being slidably mounted in a fixed hollow support carried by said first-mentioned support, with the inner end of said depth gauge extended coaxially through the hollow supporting member of the holder and into the fixed hollow support.

3. A valve stem grinder for grinding the tappet ends of the stems of tappet valves, comprising a support, a rotary abrasive grinding wheel carried by said support, a valve holder movably mounted on said support adjacent to said abrasive wheel and shiftable towards and away therefrom, said holder having a valve-supporting portion and a depth gauge-supporting portion in spaced relation to each other, each of said supporting portions having a seat, one of which seats is adapted to be engaged by the head of a valve during the stem-grinding operation, with the stem projecting towards the abrasive wheel, an adjustable depthgauge removably seated upon the other seat of said valve holder during the stem-grinding operation and movable with said holder, said depth gauge having an inner end projecting inwardly from the seat in the depth gauge-supporting portion in parallel relation to the valve-supporting portion, and a relatively fixed abutment carried by the first-mentioned support for abutting engagement with the inner end of said depth gauge to limit the movement of the holder and the valve being ground according to any pre-selected setting of the depth gauge in the valve position in an engine to the measurement from the valve seat to the tappet of the engine, said valve holder including a hollow supporting member axially extended from one side of the depth gauge engaging seat, said supporting member being slidably mounted in a fixed hollow support carried by said first-mentioned support, with the inner end of said depth gauge extended coaxially through the hollow supporting member of the holder and into the fixed hollow support, and said relatively fixed abutment being carried by an axially adjustable fixture slidably mounted on the fixed hollow support.

4. A valve stem grinder for grinding the tappet ends of the stems of tappet valves, comprising a support, a rotary abrasive grinding wheel carried by said support, a valve holder movably mounted on said support adjacent to said abrasive wheel and shiftable towards and away therefrom, said holder having a valve-supporting portion and a depth gauge-supporting portion in spaced relation to each other, each of said supporting portions having a seat, one of which seats is adapted to be engaged by the head of a valve during the stem-grinding operation, with the stem projecting towards the abrasive wheel, an adjustable depth gauge removably seated upon the other seat of said valve holder during the stem-grinding operation and movable with said holder, said depth gauge having an inner end projecting inwardly from the seat in the depth gauge-supporting portion in parallel relation to the valve-supporting portion, and a relatively fixed abutment carried by the first-mentioned support for abutting engagement with the inner end of said depth gauge to limit the movement of the holder and the valve being ground according to any pre-selec'ted setting of the depth gauge in the valve position in an engine to the measurement from the valve seat to the tappet of the engine, said valve holder including a hol- 10w supporting member axially extended from one side of the depth gauge engaging seat, said supporting member being slidably-mounted in a fixed hollow support carried by said first-mentioned support, with the inner end of said depth gauge extended coaxially through the hollow supporting member of the holder and into the fixed hollow support, and said relatively fixed abutment being carried by an axially adjustable fixture slidably mounted on the fixed hollow support, with the abutment extended through an elongated slot in one side of said fixed hollow support,

5. A valve stem grinder for grinding the tappet ends of the stems of tappet valves, comprising a support, a rotary abrasive grinding wheel carried by said support, a valve holder movably mounted on said support adjacent 'to said abrasive wheel and shiftable towards and away therefrom, said holder having a valve-supporting portion and a depth gauge-supporting portion in spaced relation to each other,-each of said supporting portions having a seat, one of which seats is adapted to be engaged by the head of a valve during the stem-grinding operation, with the stem projecting towards the abrasive wheel, an adjustable depth gauge removably seated upon the other seat of said valve holder during the stem-grinding operation and movable with said holder, said depth gaugehaving an inner end projecting inwardly from the seatin the depth gauge-supporting portion in parallel relation to the valve-supporting portion, and a relatively fixed abutment carried by the first-mentioned support for abutting engagement with the inner end of said depth gauge to limit the movement of the holder and the valve being ground according toany pre-selected setting of the depth gauge in the valve position in an engine to the measurement from the valve seat to the tappet of the engine, said valve holder including a hollow supporting member axially extended from one side of the depth gauge engaging seat, said supporting member being slidably mounted in a fixed hollow support carried by said first mentioned support, with the inner end of said depth gauge extended coaxially through the hollow supporting member of the holder and into the fixed hollow support, said relatively fixed abutment being carried by an axially adjustable fixture slidably mounted on the fixed hollow support, and means for axially adjusting said fixture to change the position of said abutment,

6. A valve stem grinder for grinding the tappet ends of the stems of tappet valves, comprising a support, a rotary abrasive grinding wheel carried by said support, a valve holder movably mounted on said support adjacent to said abrasive wheel and shiftable towards and away therefrom, said holder having a valve-supporting portion and a depth gauge-supporting portion in spaced relation to each other, each of said supporting portions having a seat, one of which seats is adapted to be engaged by the head of a valve during the stem-grinding operation, with the stem projecting towards the abrasive wheel, an adjustable depth gauge removably seated upon the other seat of said valve holder during the stem-grinding operation and movable with said holder, said depth gauge having an inner end projecting inwardly from the seat in the depth gauge-supporting portion in parallel relation to the valve-supporting portion, and a relatively fixed abutment carried by the first-mentioned support for abutting engage-- ment with the inner end of said depth gauge to limit the movement of the holder and the valve being ground according to any pre-selected setting of the depth gauge in the valve position in an engine to the measurement from the valve seat to the tappet of the engine, said valve holder including a hollow supporting member axially extended from one side of the depth gauge engaging seat, said supporting member being slidably mounted in a fixed hollow support carried by said first-mentioned support, with the inner end of said depth gauge extended coaxially through the hollow supporting member of the holder and into the fixed hollow support, said relatively fixed abutment being carried by an axially adjustable fixture slidably mounted on the fixed hollow support, means carried by said fixture and engaged with the first-mentioned support for axially adjusting said fixture to change the position of said abutment, and a dressing tool carried by said fixture and movable therewith on said fixed hollow support, said dressing tool having its operative face disposed in a predetermined relation to said abutment.

7. A valve stem grinder for grinding the tappet ends of the stems of tappet valves, comprising a support, a rotary abrasive grinding wheel carried by said support, a valve holder movably mounted on said support adjacent to said abrasive wheel and shiftable towards and away therefrom, said holder having a valve-supporting portion and a depth gauge-supporting portion inspaced relation to each other, each of said supporting portions havingsa seat, one of which seats is adapted to be engaged by the head of a valve during the stem-grinding operation, with the stem projecting towards the abrasive wheel, an adjustable depth gauge removably seated upon the other seat of said valve holder during the stem-grinding operation and movable with said holder, said depth gauge having an inner end projecting inwardly from the seat in the depth gauge-supporting, portion in parallel relation to the valve-supporting portion, and a relatively fixed abutment carried by the first-mentioned support for abutting engagement with the inner end of said :depth gauge to limit the movement of the holder and the valve being ground according to any pre-selected setting of the depth gauge in the valve position in an engine to the measurement from the valve seat to the tappet of the engine, said valve holder including a hollow supporting member axially extended from one side of the depth gauge engaging seat, said supporting member being slidably mounted in a fixed hollow support carried by said first-mentioned support, with the inner end of said depth gauge extended coaxially through the hollow supporting member of the holder and into the fixed hollow support, said relatively fixed abutment being carried by an axially adjustable fixture slidably mounted on the fixed hollow support, means carried by said fixture and engaged with the first-mentioned support for axially adjusting said fixture to change the position of said abutment, a dressing tool carried by said fixture and movable therewith on said fixed hollow support, said dressing tool having its operative face disposed in a predetermined relation to said abutment, and a cross feed connected with said dressing tool for feeding said dressing tool across said abrasive wheel to face or true the latter.

8. A valve stem grinder for grinding the tappet ends of the stems of tappet valves, comprising a support, an abrasive grinding means carried by said support, a valve holder movably mounted on said support adjacent to said grinding means and shiftable towards and away therefrom, said holder including a valve seat against which the valve is adapted to be seated when the valve is disposed in the holder for grinding the tappet end of the valve stem, an adjustable depth gauge carried by said valve holder and movable therewith during the valve stem grinding operation, said depth gauge being adjustable to any pre-selected setting in the valve position in an engine to the measurement from the valve seat to the tappet of the engine, a relatively fixed stop carried by said support and disposed in the path of the depth gauge when the latter is carried by the valve holder to limit movement of the holder and the valve being ground, and a dressing tool also carried by said support for dressing the abrasive grinding means, said dressing tool having the plane of its operative face disposed in a relatively fixed predetermined spaced position with relation to the operative plane of said relatively fixed stop with the distance from the grinding face of the grinding means to the valve seat aforesaid equal to the length of the depth gauge less the distance between the plane of the fixed stop and the plane of the operative face of the dressing tool.

9. A valve stem grinder for grinding the tappet ends of the stems of tappet valves, comprising a support, an abrasive grinding means carried by said support, a valve holder movably mounted on said support adjacent to said grinding means and shiftable towards andaway therefrom, said holder including a valve seat against which the valve is adapted to be seated when the valve is disposed in the holder for grinding the tappet end of the valve stem, an adjustable depth gauge carried by said valve holder and movable therewith during the valve stem grinding operation, said depth gauge being adjustable to any pre-selected setting in the valve position in an engine to the measurement from the valve seat to the tappet of the engine, a relatively fixed stop carried by said support and disposed in the path of the depth gauge when the latter is carried by the valve holder to limit movement of the holder and the valve being ground, a dressing tool also carried by saidsupport for dressing the abrasive grinding means, said dressing tool having the plane of its operative face disposed in a relatively fixed predetermined spaced position with relationito the operative plane of said relatively fixed stop, with the distance from the grinding face of the grinding means to the valve seat aforesaid equal to the length of the depth gauge less the distance between the plane of the fixed stop and the plane of the operative face of the dressing tool, and means common to said stop and dressing tool for simultaneously adjusting both the stop and dressing tool towards and away from the operative face of the abrasive grinding means, while maintaining the predetermined relation of the stop and dressing tool.

HARRY E. MILLER.

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