US2525119A - Valve-seat grinding means - Google Patents

Description

Oct. 10, 1-950 A. l. DUNN 2,525,119

VALVE SEAT GRINDING MEANS Filed April 9, 1947 Zhwentor 445w]; flu/v/v, 6 8g W :a M

' Gttorueg Patented Oct. 10, 1950 UNITED STATES PATENT, OFFICE VALVE-SEAT GRINDING MEAN S Allen I. Dunn, Hollywood, Calif., assignor to S & D Engineering Company, Glendale, Califl, a corporation of California App ica i Arr .9 Se ial 1 0,2 2 12 Claims. (01. 51-241).

This invention relates to mechanism for grind: in valve-seats or the like, and is particularly useful for grinding valve-seats of internal com; bustion engines, for example, automobile engines.

In grinding valve-seats, it isthe common practice to remove the valve and its stem from the cylinder block or head in which the valve-seats are located, and to insert the shank of an arbor of either the tapered or expanding type in the bore of the valve stem guide. The body of the arbor above the shank, is of a uniform diameter and suiiiciently lon to project a considerable. distance above the valve-seat to be serviced In f c n the. g ndin opera n a p r of th mechanism is supported on this arbor, with the a y r nd r hee i qo ta tw th o h ng. he val -seat- T e g n e is us al y r ta ed through the agency of a motor. T e; driving means is usually attached by a driving connec tion to the upper end of the grinder assembly. Th pe tor pu hes o n e. mo o w ich in turn bears down against the grinder assembly below it, thus applying pressure between the grinding wheel and the valve-seat. This move-. ment is preferably intermittent, so that. aftereach contact is effected with the seat, the grinder is raised slightly. This allows the cuttings to free themselves from the wheel; also eliminates all contact during acceleration qrdeceleration, which is very desirable.

All valve seat grinders in present use are of one of two ty e e the det hable r n n-d tachable. In the former a drive from the motor is accomplished, but heretofore no means has been provided to raise the grinding wheel oif; the seat, and hence intermittent grindingmovement is impossible.

In the latter, the motor and grinder assembly are non-.detachably connected, which loses the advantage of being able to raise the grinding wheel at will. This distadvantage is aggravated by the fact that since several different types of grinding wheels should often be used on the same valveeseats, for example, a roughing wheel, a finishing wheel and a wheel of a different angle for narrowing the seat, usually on the top side, the process of changing wheels on the grinding assembly adds materially to the time consumed in doing a valve job. In fact, ratherthan take this additional time, the temptation to be content with an inferior job usually prevails, simply because convenient wheel changing is impossible.

One o iect f th s inv t n is o o d a m ans of bta n th adv nta es of b t detachable and. non-det ha e y f r nd rs. which o my know d e is entirely novel- Another object of this invention is to provide a grinder assembly having a combination of parts, which will operate, in a sense, as a pilot," for; n in the p o r eve er t e grin i ass bly, an for pp r ing h ame at i fii sv The grinder unit involved in this invention,

includes an inner sleeve having a bore that tele scopes over the arbor referred to, and the drivs a n h ro ary r n e are. rotaiab y upp rte o is lee e n 2 he Ob e s i. this invention is to provide means mounted with;- in the bore of the sleeve, for holding the sleeve, sai y u a ia am unt o t on; ha is to say, the rotation of the sleeve is not p si-. tively p t d, b prev ted, b a fri tional force.

A h jec o h n en on s. o ro id frictional resistance within the" sleeve of the grinder assembly, which is of' such construction ha i c e re d ly a t d, desired, t h rmit a slight rotation of the sleeve to attain the advanta e of increased accuracy in the centering of the ground seat, which will result from the occurrence of such slight rotation.

Another object of the invention is to, produce a friction device capable of being inserted in the bore of the sleeve of a grinder unit of the type referred to, which includes means for seating itself upon the 'upperend of the arbor on which the grinder unit is centered, and which also includes means for developing frictional resistance against the inner face ofthe bore of the sleeve for the general and specific purposes referred to above, and for such purposes as will appear. in the following specification.

Further objects of the inventio Will appear hereinafter,

The. invention consists in the novel parts and combinations of parts to be described herein-. after, all of which contribute to. produce. an efficient valve-seat grinding means.

A preferred embodiment offthe invention is described in the following specification, while the broad scope of the invention is pointed out in the appended claims.

In the drawings: r Fig, 1 is a side elevation illustrating a grinder mechanism embodying my invention, and repre-. senting also a handled motor with a driving connection to the same, and indicating in dotted lines the end of a compressed air hose such as may be used in case themotor is driven by compressed air.

Fig. 2 is a vertical section taken on the line 2 -2 of Fig. 1, through the mechanism embodying invention, and illustrating the same ape.

the same parts, but illustrating the friction device I that I employ within the bore of the sleeve in its extended or normal position, at which time it holds the body of the grinder assembly and the rotary grinder in an elevated position with the rotary grinder at a considerable distance above the valve-seat.

Fig- 4 is a fragmentary view, and is a vertical section upon an enlarged scale, taken through a portion of the sleeve of th grinder assembly, and illustrating more in detail the construction of the: friction device that I employ in the bore of the grinder sleeve; and this view shows the upper end of the arbor broken away, with the lower portionof the friction device resting upon the same;

Referring more particularly to the parts, I indicates a portion of a cylinder block, or head, or other housing in which a valve chest is formed, and .presenting a face 2 at which valve-seats are formed, such as the seat 3 shown in Figs. 2 and 3. The usual valve stem guide 4 is illustrated, with a bore 5 for the valve stem.

, It is common practice to insert an arbor in thi's'guidebore 5, forwhich purpose I employ an arbor with a tapered shank 6 that fits tightly in the bore 5, and which is provided above with a straight; round, or cylindrical body I. On this body I the grinder assembly is mounted, and of course this arbor functions as a guide for the inner sleeve 8 of the grinder assembly, the bore 24 of, which fits neatly on it. The lower end of this inner sleeve 8 is of reduced diameter to form a downwardly extending neck 9 so that a bearing shoulder I is formed at the lower end of the body of theisleeve, at which a bearing is placed, preferably a ball bearing I I.

'Theuppe'r endof the sleeve has a similar reduced neck I2 so that a bearing shoulder I3 is formed, at which a ball bearing I4 is mounted. Adjacent to the seat 3 a rotary grinder I is supported for rotation on the bearings I I and I4. This grinder is in the, form of a small wheel or burr,the lower end of which has a conical face I.5 on the taper that is desired for seat 3, and this taper is of course usually the same as the taper of the seatwhen the grinder unitis to perform a re-grinding job. I I

Permanently cemented in the upper end of this grinding wheel I5 is an internally threaded bushing 23,.which fits Onto the externally threaded nipple 22 which constitutes, through the horizontal wall 2I, an extension of the outer shell orcasing of ,the .grinder assembly. At the upper end of this shell 20, externally formed threads I9 provide a mounting for the internally threaded cap II, on the upper end of which is formed a 'polygonal (preferably hex) coupler head I8, over which a coupling socket of similar shape projecting from the output shaft of the drivingmotor, can be placed at Will for rotating the assembly.

The bore 24 of the inner sleeve 8, fits neatly to the diameter of the body of the arbor I, and telescopes over it when the grinder assembly is put in place for a grinding operation. In this bore 24 I provide means for enabling the grinder assembly to set itself automatically, as it were, at the proper level to enable the grinder wheel to engage the seat 3 on application of downward pressure of the motor against the grinder assembly, and to lift the grinder assembly away from the seat, when the operator raises the motor. This means that I employ within the bore 24, is indicated generally by the reference numeral 25, and this assembly 25 constitutes frictional means not only for accomplishing the purpose of setting the grinder wheel [5 at the proper level, but also operates to develop a frictional resistance against the face of the bore 24 so as to hold the inner sleeve against rotation when the driving head I3 rotates the outer sleeve 2!] and the grinder wheel at a high speed. In my invention the rotary grinder is supported so that it is floating over the valve-seat, that is to say, it is freely movable up or down.

Fig. 2 shows the assembly 25 in a collapsed condition, which it will have if it has been placed in the lower end of the bore 24 when the grinder assembly is applied and pushed down over the arbor 1. This friction device 25 includes a base 26 which is adapted to rest upon the upper end of the arbor body I, and includes also the head 2'! that fits neatly within the bore 24. The construction at the head 21 provides means for developing lateral pressure against the face of the bore 243, and in order to accomplish this, I prefer to provide a small bore or drilled socket 28 that is drilled into the side of this head 21; and in this socket a friction head 29 fits, that is forced outwardly by a coil spring 30 seated at the bottom of the socket. This small friction head 29 may be provided with a convex tip 3| on a small radius,

preferably equal to the radius of the bore 24, where it thrusts against the wall of the bore. Although this spring is a small spring, it exerts considerable force, and this force is sufficient to of hourglass type so as to prevent its wraps at its waist, from interfering with the free collapsing of this spring.

As already stated above, when the grinder assembly is applied over the body 1 Of the arbor, this friction device 25 is inserted in the lower portion of the bore 24, that is to say, it is far enough down in the bore to insure that when the grinder assembly is pushed down far enough to bring the tapered face I6 against the seat 3, the upper end of the arbor body will stop the downward movement of the base member or spring seat 26 and cause the compression of the spring 32 against the friction head 21, as illustrated in Fig. 2. Then when the grinder assembly is released, the spring 32 will extend itself as indicated in Fig. 3, and this will lift the grinder assembly to a considerably elevated position above the seat 3 by reason of the substantial frictional force that is developed at the friction head 29 against the face of the bore 24. So, when the grinding operation is ready to be accomplished, the grinder assembly will be supported above the seat 3. This is anemia the normal position for the grinder when the grinding operation starts.

Any suitable means may be employed for rotating thedriving head I! at a high speed. There are several types of driving heads, some of which include an electric motor,- and othersv of which include a small motor operated by compressed air. This is the type of driving device illustrated in Fig. l, which includesv a, substantially cylindrical body portion 34 that houses thev air motor (not illustrated) which is made integral, with. a handle 35, the outer end of which is provided with means for attaching an air hose indicated by the dotted lines. 36. Projecting down from the. lower end of the motor is a driving socket 31, thechamber of which fits over. the hexagonal head t8 of the driving head If! of the assembly. However, the connection between the driving socket 3'! and the hexagonal head i8, is merely a telescoping connection. The. grinding operator presses the operating head 38 of the valve, to

admit compressed air t the motor in the motorhousing 34, to effect the driving of the grinder assembly, and as he does so, of course he exerts a downward pressure on thehandle 35 that carries the grinder wheel down against the seat 3. This operation is accomplished intermittently for practical reasons. After each downward pressure, the operator pulls up slightly on the handle 35, and when he does so, the spring 32 elevates the grinder assembly so that it follows the driving socket 31. In practice, of course the lift of the grinding face it above the seat 3, is very slight, and would be even less usual1y,-than that indicated by the dotted line Mia in Fig. 3, that indicates a position the grinding face i6 may have with relation to the seat after each lifting movement.

An opening Fla is provided in the upper end of cap ill for the insertion of a small pin (not shown). Such a pin must be used, after the completion of each seat, provided the arbor in the next seat to be ground happens to be lower than the one just finished. The function of this pin is to push the friction device downward far enough to contact the top of the arbor in this lower position.

It will be observed that the employment of my friction device 25 determines a level for the grinder assembly that will maintain the grindin face it normally at a slight elevation above the seat 3, regardless of the height of'the upper end of the bod I of the arbor above the seat.

Furthermore, by reason Of the fact that the friction device is completely encompassed by, the

bore 24, the grinder assembly balances itself perfectly with respect to its axis of rotation. And the pressing force of the friction head 29 against the wall of'the bore 24, is perfectly balanced by the force exerted by the opposite side of the friction head or piston head 29 against the opposite side of the bore. Although the friction device does hold the inner sleeve 8 substantially fixed, nevertheless, by reason of the fact that this holding is accomplished by frictional means, there usually isa slight creeping of the sleeve 8 around the axis of the arbor, and this creeping effect is most desirable, and assists in accomplishing perfect centering of the ground seat on the axis of the arbor body 1.

Many other embodiments of the invention may be resorted to without departing from the spirit of the invention.

I claim as my invention:

1. In grinding mechanism to be applied to a centering arbor when grinding a valve-seat or the like, co-axial withthe arbor, the combination of a sleeve havingv a bore fitting freely over the arbor, arotary grinder mounted for rotation on said sleeve, and a, friction device received within the bore of the sleeve, including a base adapted torest against the endv of the arbor, a spring seating onsaid base and extending upwardly in said bore, and a friction-head within the bore against which said spring thrusts, said friction-head having means for maintaining pressure against the face of said bore.

2; In grinding mechanism, to be applied to a centering arbor when grinding a valve-seat or the like, co-axial with the arbor, the combination of a sleeve having a bore fitting freely over the arbor, a rotary grinder mounted for rotation on said sleeve, and a friction device'reoeived within the bore of the sleeve, including a base adapted to rest against the end. of the arbor, a spring seating on said base and, extending upwardly in said bore, and a friction-head within the bore against which said spring, thrusts, said friction-head having means for maintaining pressure against the face of said bore, said friction-head being capable of developing sufiicient frictional resistance on the face of the bore, to effect the compression of said first named spring.

3. A friction device for insertion into the bore of the sleeve of a valve-seat grinder or the like, which sleeve is to be telescoped over the end of a centering arbor, the combination of a base member and a friction-head capable of being introduced into the bore of the sleeve, said base member being of substantially disc form and adapted toseat against the end of the arbor; a spring connecting said base member and said friction-head, said friction-head having a spring and means associated therewith for exerting la"- eral thrust against the face of the bore of the sleeve to develop frictional resistance upon the sleeve.

, 4. In grinding mechanism to be applied to a centering arbor when grindinga valve-seat or the like, co-axial with the arbor, the combination of a sleeve having a bore telescoping freely over the arbor, a rotary grinder mounted for rotation on said sleeve and having adriving-head at its upper end adapted to be rotated, and pressed downwardly intermittently to bring the grinding face of the grinder into contact with the seat being ground; and a friction device carried in said bore at a sufiiciently low level to be engaged by the upper end of the arbor when the sleeve is telescoped over the same, said friction device including a compression spring to thrust against the end of the arbor, and a friction-head operatively connected'with the upper end of said spring, said friction-head having means for developing sufficient friction against the face of said bore to effect a compression of the spring when the sleeve is forced downwardly far enough to bring the rotary grinder substantially into contact with the valve-seat, thereby enabling the spring to lift the rotary grinder and support the same out of contact with the valve-seat.

5. In a valve-seat grinding mechanism for sup porting a rotary grinder floating adjacent to the valve-seat, for co-operation with a rotary driving head; the combination of an arbor supported with its axis coinciding with the axis of the valveseat, a centering bearing mounted to slide freely along said arbor, a rotary member mounted for rotation on said bearing member and for movement. in unison with the bearing member along said arbor, a rotary grinder carried by said rotary member, a friction-head carried by said bearing member, guided along the same, and having means for engaging the bearing member to develop frictional force resisting movement of the friction-head along said bearing member, said frictional force capable of supporting the weight of the grinder and its attached parts, compressible means located between the end of said arbor and said friction head, said friction-head operating when the driving head exerts downward pressure, to compress the said compressible means; said compressible means operating to lift the rotary grinder oil the seat when the said downward pressure ceases.

6. In a valve-seat grinding mechanism for supporting a rotary grinder floating adjacent to the valve-seat, for co-operation with a rotary driving head; the combination of an arbor supported with its axis coinciding with the axis of the valveseat, a centering bearing mounted to slide freely along said arbor, a rotary member mounted for rotation on said bearing member and for movement in unison with the bearing member along said arbor, a rotary grinder carried by said rotary member, a friction-head carried by said bearing member, guided along the same, and having means for engaging the bearing member to develop frictional force resisting movement of the friction-head along said bearing member, said frictional force capable of supporting the weight of the grinder and its attached parts, compressible means located between the end of said arbor and said friction-head, said friction-head operating when the bearing member is forced down over the arbor to compress said compressible means against the end of the arbor, so that when the force acting on the bearing member ceases, the compressible means will expand and lift the grinder away from the valve-seat.

'7. In a valve-seat grinding mechanism for supporting a rotary grinder float ng adjacent to the valve-seat, for co-operation with a rotary driving head; the combination of an arbor supported with its axis coinciding with the axis of the valve-seat, a centering bearing mounted to slide freely along said arbor, a rotary member mounted for rotation on said bearing member and for movement in unison with the bearing member along said arbor, a rotary grinder carried by said rotary member, a friction-head carried by said bearing member, guided along the same, and having means for engaging the bearing member to develop frictional force resisting movement of the friction-head along said bearing member, said frictional force capable of supporting the weight of the grinder and its attached parts; and a spring between the end of the arbor and the friction-head for returning the grinder to its floating position adjacent the valve-seat; the frictional force between the friction head and the bearing member being capable of supporting the grinder and its attached parts in its floating position with the grinder out of contact with the valve-seat.

8. In grinder mechanism to be applied to a centering arbor when grinding a valve-seat or the like, coaxial with the arbor, the combination of a sleeve having a bore fitting freely over the arbor, a rotary grinder, a driving-head connected with the rotary grinder for rotating the same, and adapted for connection to a rotary driving member; bearing means for rotatably mounting the rotary grinder on the sleeve, a friction-head fitting within the bore of the sleeve, with resilient means for exerting lateral pressure against the face of the bore to develop resistance to the rotation of the sleeve; all of said parts cooperating to enable the rotary grinder to be supported out of contact with the valve-seat when the operator of the grinder reverses the direction of his downward pressure on the driving head.

9. In grinder mechanism to cooperate with a rotary driving socket, for grinding a valve-seat or the like, the combination of an arbor supported with its axis coinciding with the axis of the seat, an inner sleeve telescoped over said arbor, a piston in said sleeve above the upper end of the arbor, so that a chamber is formed within said sleeve below the piston, a grinder, an outer sleeve with bearing means supporting the same for rotation on the axis of said first named sleeve, and having a coupler head at its upper end for driving the same, yielding means within said chamber for exerting force against the under side of said piston, said piston having friction means associated therewith for developing sufficient friction against the bore of the inner sleeve to enable said yielding means to normally support the grinder floating yieldingly above, and adjacent to, the said seat, all of said parts cooperating when a driving socket is pressed down on the driving head, to impart movement through the friction means to the grinder to depress the same into contact with the valve-seat, said yielding means operating when the downward pressure ceases at the outer sleeve, to lift the grinder out of contact with the valve-seat.

10. In grinder mechanism to be applied to a centering arbor when grinding a valve-seat or the like, coaxial with the arbor, the combination of a sleeve having a bore fitting freely over the arbor, a rotary grinder, a driving-head connected with the rotary grinder for rotating the same, and adapted for connection to a rotary driving member, bearing means for rotatably mounting the rotary grinder on the sleeve, a friction means mounted in the bore for developing frictional resistance between the sleeve and the arbor, including a friction shoe touching against the surface of the bore, a spring thrusting substantially radially with respect to the arbor, pressing the shoe against the surface of the bore, another spring located between the friction means and the arbor for exerting thrust upwardly against the friction means, said friction means and said last named spring cooperating to normally support the grinder floating yieldingly out of contact with the work except when downward pressure is applied to the driving head to overcome the resistance of said friction connection and depress the grinder onto the valve-seat; said friction connection and said last named spring cooperating when downward pressure on the driving head ceases, to lift the grinder off of the valve-seat.

11. In grinder mechanism to be applied to a centering arbor when grinding a valve-seat or the like coaxial with the arbor, the combination of a sleeve having a bore fitting freely over the arbor, a rotary grinder, a driving-head connected with the rotary grinder for rotating the same, and adapted for connection to a rotary driving member, bearing means for rotatably mounting the rotary grinder on the sleeve, and friction means located wholly within the circumference of said bore, and seating on the end of the arbor for frictionally resisting the shifting of the sleeve, up and down on the arbor, the said friction means capable of supporting the outer sleeve floating yieldingly, with the grinder out of contact with the valve-seat; and. a spring associated with REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Howser Jan. 5, 1932 Albertson Feb. 19, 1935 Albertson June 2, 1936 Weynand Feb. 12, 1946 Chiles Nov. 25, 1947

Images