US1933016A

US1933016A - Valve grinder

Info

Publication number: US1933016A
Application number: US392164A
Authority: US
Inventors: Huse John Oldham
Original assignee: Individual
Current assignee: Individual
Priority date: 1929-09-12
Filing date: 1929-09-12
Publication date: 1933-10-31
Anticipated expiration: 1950-10-31

Description

Oct-31, 1933. J. o. HusE 1,933,016

A VALVE GRINDER Filed sept. 12, 1929 2 sheets-Sheet 1 J'on HUSS vri/s ATTORNEYs oct. 31, 1933. J o, HUSE i 1,933,016

VALVE GRINDER Filed Sept. 12, 1929 2 Sheets-Sheet 2 ,Patented 9ct. 31, 1 933 VALVE GRINDER I John Oldham Huse, Berlin, Germany Application September 12, 1929 Serial No. 392,164`

10 Claims. (Cl. 51-241) My present invention relates to grinding machines and particularly to machines adapted to reface valve seats by grinding and truing them to predetermined limits. Inrefacing valve seats, it is customary to employ either a steel cutting tool or a grinding apf Aparatus in which the cuttingv element has to be pre-ground or pre-trued to the angle of the valve seat. This is a great disadvantage because in l .the case of the cutting tools it requires a large expensive machine to re-grind the cutting elements and asa consequence these cutting tools are frequently scrapped as soon as the cutting edge becomes deformed. In the event that a grinding apparatus is used, it is inconvenientto provide a dressing device for the grinding wheel and even when such device is provided, it is necessary to dress the grinding wheel comparatively frequently in order to ensure accurate grinding. The general object of the present invention is to overcome these defects by providing a valve grinding device so constructed that the grinding Wheel is substantially self dressing.

Another object of the invention is to provide a valve grinding mechanism in which the grinding wheel does not have to be trued to the angle of the valve seat during the grinding operation, and yet which grinds the seat accurately to the desired angle.` 1 The invention also has for its object the provision o f a power driven grinding wheel adapted togrind valve seats and means for mounting the same to swing concentrically with the axis ofthe cylinder or like element uponwhich the valve is seated.

A still further object of the invention is to'provide means whereby the application of the grinding wheel to the valve seat is manually controlled and the depth of the metal to be removed is automatically limited by ready preadjustment of th valve grindingmechanism.

With the foregoing and other and more particular objects in view, as hereinafter pointed out, my invention comprises the features of improvement `set forthand described below and illustrated in the accompanying drawings forming a part of this -specification, and in which are shown two embodiments thereof.

In these drawings,

Fig. 1 is an elevation, partly inlsection, of a grinding machine operatively associated with the valve seat of an engine. Y

Fig. 2 is a view taken on line 22 of Fig. 1, looking' inthe direction of the arrows. Q

Fig. Bis a View taken on line '3 3 of Fig. 1

'4 with the driving motor removed.

but with the driving motor shown in elevation. Fig. 4 is a view similar to Fig. 1 of a modified form of grinding machine, and 4 Fig. 5 is `a section taken on line 5-5 'of Fig. 60 Referring rst to Figs. 1 to 3 inclusive, th valve seat 10 is. atl -the top of the cylindrical opening 11 in the engine casting 12 and the stem of the valve slides i-n' the guide bore 13 in the casting 12. The valve is of course removed'when 65 the seat lis ground. A motor 14 suitably connected to a power source has a shaft 15 on' the lower end of which a carborundum or like surfaced grinding wheel 16 is removably mounted by means of the nut 17 and its lcooperating 70 Washers.

The grinding wheel 16 is provided with a cutting face 18 at one end and the wheel is mounted so 'that the cutting face moves across the face of the cone forming the valve seat 4from top to bot- 75 tom or vice versa'rather than in a direction circumferentially of the valve seat. The grinding wheel preferably has an annular cutting face as shown in the drawings, and this can be most conveniently provided by employing -a cup-shaped wheel so as to" facilitate its mounting upon shaft l5.

Motor 14 is slidably and adjustably mounted upon a bracket 19 which is pivoted by means of bolt '20 to the top of a stem 21 that extends 85 downwardly into the valve stem guide or bore 13 to whose internal diameter -it is adapted by the cylindrical bushing '13. The adaptor bushing ts the bore 13 snugly enough so 'that it y will not turn. The bushing is provided with a knurled head to facilitate its insertion in and removal lfrom the guide bore. The knurled'head also limits the distance to which the bushing may be pushed into the bore, and the elevation of the upper surface of this head is thus ii'xed 95 bythe elevation of the top of the valve guide.

f The knurled head is rounded underneath so that a tool may be forced underneath the head to remove the bushing in ca se it sticks in the bore. 1

The stem 21 is machined to a nice turning and 100. sliding t, in Ybushing 13. Hence the motor mounting may be turned manually so as to swing the grinding wheel around the entire circumference of the valve seat.

In practice, a set of bushings of hardened steel are provided, each havingy an interior bore fitting the stem 21, but of varying outside diameters' to lit valve guides of different sizes. .In this way the same grinding tool'can be used to reface valve seats of a large range of sizes. In practice also, 110,

contact with the valve seat.

valve stems increase in size in uniform increments of say one-sixteenth or one-eighth of an inch, and consequently a number of adaptor bushings 13' are made for each size with their external diameters varying only by a few thousandths of an inch. Thus when the valve guides become enlarged through wear, it is an easy matter to select one of these bushings of the right outside diameter to fit closely and rmly within the bore of the valve guide.

The downward movement of stem 21 is limited, when the stem is placed in the bushing 13' by means of a shoulder 22 which engages the upper end of the bushing. The position ofthe shoulder 22 is therefore determinedby the position of the top of the valve guide.

In order to mount the motor 14 on bracket 19, a part 23 is secured to the side of the motor by means of screws 24 and this part is provided with sliding dove-tailed guide ways 25 by which it is held to the bracket 19; Bracket 19 is provided with an adjusting screw 26 which is mounted for rotation in the bracket and held against longitudinal' movement by the shoulders 27 at the lower end. This adjusting screw is threaded through a lug 28 which projects from part 23, and by turning the knurled head of the screw with the fingers, the part 23 is made to slide in' one direction or the other in the dove-tailed Ajoint 25, thus raising or lowering motor 14 and the grinding wheel 16.

The lower end of bracket 19 terminates in a pair of ears 29 which t snugly over the flattened sides of the head 30 and may be clamped against them by tightening a nut 31 on the right hand end of bolt 20 as viewed in Fig. 2. The head 30 is recessed centrally so as to allow clearance for the lower end of adjusting screw 26.

The method of utilizing my improved grinder is as follows:

The proper adaptor bushing 13' is chosen to t the bore of the valve guide and is forced into the bore by hand. The inclination of bracket 19 is set to correspond. approximately to the inclination of the valve seat which is to be refaced. The stem 21 is theninserted in the bore of guide 13 in place of thevalve stem. The adjusting screw 26 is turned to'raise'the grinding wheel sufciently so that shoulder 22 may rest upon the top of the valve guide without having the grinding Wheel in The motor 14 is then energized and adjusting screw 26 is revolved carefully until a spark is struck by the rotating grinder against the valve seat.

The grinding tool is lifted manually the instant the spark is struck, shoulder 22 rising away from the top of the valve guide, and the valve seat is examined to see whether or not the grinding wheel is cutting clear across the face of the seat. If it is not so cutting, the angle of bracket 19 is adjusted and the grinding wheel is again lowered to strike another spark. This is repeated until the grinding wheel just grazes evenly across the whole face of the valve seat. When this adjustment has been secured the axis of the shaft A15 is at the proper angle to the axis of stem 21.

A further slight downward adjustment of screw 26 is then made so as to allow the cutting surface of the grinding tool to descend far enough to take l the desired cut from the valve seat. Then, the motor being energized, the tool is lowered carefully by hand until the Wheel begins to grind the seat, and the grinding tool is swung around slowly by hand over the' entire circumference of thev valve seat. When the complete vcut 11615 been taken, further downward movement of the stem 21 will be limited by shoulder 22 and grinding will cease. If sufficient metal has then not been ground away to remove the wear from the valve seat, a second adjustment of the screw 26 is made, and the operation is repeated so as to make another'cut.

It willbe understood that the axis of the grinding wheel shaft intersects or approximately lntersects the axis of the cone of which the valve seat is a segment, this axis being coincident with the axis of cylinder 11 upon which the valve seat is placed, and also coincident with the axis of the valve stem guide 13. It will also be understood that the axis of the grinding wheel shaft passes approximately through the middle of the valve seat 10 so as to substantially bisect the same. The axis of the grinding Wheel shaft is normal to the segment of the cone forming the valve seat. Hence when the rotating grinding wheel is brought into contact with the seat, grinding will take place equally at two diametrically opposite portions of the grinding wheel, one in front of and the other in back of the plane on which the section of casting 12 is taken in Fig. 1.

If we consider for a moment a grinding wheel in which the cutting face is at right angles to the axis of shaft 15 instead of being rounded as shown in the drawings, the grinding surface will be' a circular line at the outside periphery of the grinding wheel. This line as the grinding wheel rotates under the action of the electric motor will move across the straight face of the conical valve seat, downwardly on one side and upwardly on the other, and, assuming that the outside edge of the wheel is a true circle, it will make contact ,with the edge of the valve seat all the way across the face thereof. Hence as the axis of shaft 15 is swung around the axis of stem 21, the action of the grinding wheel will be to produce a true Conical valve seat.

As grinding progresses, the abrading action or wear on the cutting face of the grinding wheel itself will result merely in agwidening of the cutting face which at the start we assumed to be a circular line.` Ultimately the width of this line will extend over the entire width of face 18. It will thus be understood that the abrasive wear on the cutting face of the wheel does not interfere with the grinding of a valve seat which is truly conical in form. In other words, thegrinding wheel is self dressing and it is not necessary to provide additional mechanism in the form of a diamond point for periodically re-shaping the face of the grinding wheel.

Referring now to Figs. 4 and 5 of the accompanying drawings, the motor 14a is held in a clamping device comprising two pair of split semi-circular arms 32 which extend froma common base and embrace the motor, being-drawn into adjustable clamping engagement therewith by means of screws 34. The base 33 of the clamping device is pivoted to the upper end of stem 21a.in a similar manner to the pivoting of bracket 19 on stem 2l. That is, the angle of the axis of grinding wheel 16a with respect to the axis of stem 21a can be'va'ried as desired by means of adjusting nut 31a.

Stem 21a is received in the bore 'of valve guide 13 the same as stem 21 and in this way centers the grinding mechanism with respect to the cylinder 11 on valve seat 10. In place of'p'roviding the bracket 19 and the adjusting screw 26, the cutting face 18a of the grinding Awheel is maintained in proper cutting relation with the 1 seat 10 by means of an adjusting collar 35 and locknut 36 which are threaded upon stem 21a.

Adjusting collar 35 forms a shoulder which is vertically adjustable with respect to the stem for limiting the downward movement of the stem within guide 13, and locknut 36 provides means for setting the adjusting collar against rotation on the stem and hence secures itl in adjusted position. Stem 21a is slotted centrally through its threaded portion so that the two halves of the stem opposite the slot may be forced outwardly to secure a snug t of the nut and collar upon the threads.

This modified form of grinding machine is operated similarly to the form shown in Fig. 1

except that instead of adjusting the depth of cut by means of adjusting screw 26, this is accomplished by loosening locknut 36, turning collar 35, and then resetting the locknut. Also by loosening screws 34 motor 14a may be adjusted in position axially thus moving the cutting face 18a ofthe grinding wheel toward or away from the axis of stem 21a, without changing the angular position of the axis of the motor shaft with respect tothe axis of the stem. Because of the provision of this adjustment in addition to the vertical adjustment of stem 21a, valve seats of didering diameters may be refaced without changing the angle of the valve seat.

With the grinding mechanism shown. in Fig. 1, the adjustment obtained by adjusting screw 26 and guide ways 25 corresponds to the adjustment obtained by loosening screws 34 and shifting the motor in the arms 32 of Fig. 4, and since there is no means shown in Fig. 1 for adjusting the vertical height of stem 21, when it is desired to grind a valve seat of smaller or larger diameter than the one illustrated, it is necessary to change the angle of the valve seat accordingly. ever, that the stem 21 of Fig. 1 may be provided with the adjusting collar 35 and locknut 36, or that the motor mounting shown in Fig. 1 may be used with the stem 21a as shown in Fig. 4.

It will be understood that because of the fact that the upper end of stem 21 is offset so that the center of the pivot of the base 33 on stem 21a is to the left of the axis of stem 21a as viewed in Fig. 4, the axis of the motor-and grinding wheel can be brought closer to the axis of the valve stem and consequently with this form of construction the grinding device can be used for grinding valves of somewhat smaller diameter than the device shown in Fig. 1.

While I have shown and described only two forms of apparatus adapted for the grinding of large valve seats, I do not wish to be understood as intending to limit my invention thereto, since I consider such forms merely as examples of a diversity of forms in which I believe my invention to be capable of being practiced within the scope of the appended claims.

I claim:-

1. In a valve seat grinder, a rotatably driven shaft, a grinding wheel having an end cutting face mounted on the shaft, and means for rotatably supporting said shaft with its axis intersecting and extending downwardly from the axis of the valve seat and directing the cutting end of the grinding wheel against the valve seat, said means being capable of swinging the shaft around the valve seat while maintaining the axis at a desired angle to the valve seat.

2. In a valve seat grinder, a rotatably driven shaft, a grinding wheel having an annular cut- It will be understood, how.

ting face mounted on the shaft, and means for rotatably supporting said shaft with its axis intersecting and extending downwardly from the axis'of the valve seat and directing the cutting end of the grinding wheel against the valve seat, said means being capable of swinging the shaft around the valve seat while maintaining the axis at a desired angle to the valve seat.

3. A valve seat grinder comprising a stem adapted to be received in the valve guide bore, a rotatably driven shaft having mounted upon one end thereof a grinding wheel having a cutting face at one end, and means for rotatably supporting the grinding wheel shaft on the stem with the axis of said shaft normal to the valve seat and directing the cutting face of the grinding wheel against the valve seat.

4. A valve seat grinder comprising a stem adapted to be received in the valve guide bore, a rotatably driven shaft having a rotary abrasive wheel mounted upon one end thereof, and means pivoted on the stem for rotatably supporting said shaft with the axis of the shaft normal to the` surface being ground.

5. A valve seat grinder comprising a stem adapted to be received in the valve guide bore, a rotatably driven shaft, means pivoted onV the stem for rotatably supporting the shaft with its axis at an angle to the axis of the stem and intersecting the valve seat, and a rotary abrasive wheel having a cutting face upon one end thereof mounted at the lower end of the rotatably driven shaft, and means for adjusting the height of the cutting face of the cutter with respect to the valve seat so as to secure a predetermined depth of cut. l

6. A valve seat grinder comprising a stem adaped to be received in the valve guide bore, a rotatably driven shaft having a rotary abrasive wheel mounted upon one end thereof, said wheel having an annular cutting face on its outer end, and means pivoted on the stem for rotatably supporting said shaft with the axis thereof extending downwardly and intersecting the valve seat, and means for adjusting the cutting face of the grinding wheel with respect to the valve seat so as to secure a predetermined depth of cut.

7. A valve seat grinder comprising a stem adapted to rotate and slide vertically in the valve guide bore, a rotatably driven shaft having mounted upon one end thereof a grinding wheel having a cutting face at one end, means for rotatably supporting the grinding wheel shaft on the stem with the axis of the shaft normal to the valve seat and directing the cutting face of the grinding wheel against the valve seat, and means for limiting the downward movement of theA stem.

8. A valve seat grinder comprising a stem adapted to rotate and slide vertically in the valve guide bore, a rotatably driven shaft having mounted upon one end thereof a cup shaped grinding wheel with an end cutting face, means for rotatably supporting said shaft with the axis thereof normal to the valve seat and directing the cutting face of the grinding wheel against the valve seat, and means on said stem to limit the downward movement of the stem.

9. A valve seat grinder comprising a stem supporting the grinding wheel shaft with the axis upper end of the stem, means for limiting the downward movement o! the stem within the valve guide bore, a motor slidably mounted upon the bracket, an adjusting screw operatively associated with the bracket and the motor so as to cause the motor to slide relatively to the bracket, and an armature shaft for the motor having a grinding wheel mounted upon the end of the shaft and provided with a cutting face. at its outer end.

JOHN OLDHAM HUBL'.